جستجوی مقالات مرتبط با کلیدواژه « ترکیب پذیری عمومی » در نشریات گروه « زراعت »

Low diversity and poor genetic basis of germplasm in temperate regions is a significant challenge in maize breeding. Maize germplasms from tropical and subtropical regions often contain a broader genetic base and show larger diversity than germplasms from temperate regions. Therefore, it seems that foreign germplasms, especially germplasms from tropical and subtropical regions, can be used as a potential solution to strengthen the genetic base of germplasm in temperate regions. However, the efficiency of screening methods to identify superior and suitable sources of foreign germplasm remains a major challenge. The objective of this study was to determine the optimum number of testers and select suitable testers for screening maize lines derived from tropical and subtropical CIMMYT germplasm.

In this experiment, three testers of temperate regions (MO17, B73, K1264/5-1) were crossed with 25 lines originated from the CIMMYT maize germplasm based on line × tester mating system. A total of 75 crosses along with the control hybrid (SC704) were evaluated in alpha-lattice experimental design in two replications each with four incomplete blocks in two regions (Moghan and Jiroft). Analysis of variance was done based on line × tester method, as well as separation of the effect of crosses into its components using the method suggested by Kemptorn (1957). GGE-biplot graphical analysis based on the methodology proposed by Fan et al. (2010) was also used to estimate the effects of general combining ability (GCA) and specific combining ability (SCA).

The results showed that out of the 75 crosses, 32 crosses had higher and significant grain yield compared to the control hybrid SC704. The superiority of the superior cross compared to the control hybrid ranged from 1.46 to 3.77 tons per hectare. These findings highlighted the potential of utilizing tropical and subtropical CIMMYT germplasm to enhance maize yield in temperate regions of Iran. Based on the results, the lines No. 22, 9, 19, 12, 20, 5, 17, 21, 24, 14, 15, 23, and 11 had the highest positive GCA for grain yield, respectively. In general, in terms of grain yield, GCA, and SCA, it is possible to directly use lines No. 4, 5, 9, 11, 12, 19, 22, and 24 extracted from tropical and subtropical CIMMYT germplasm to improve grain yield in temperate regions. Evaluating the efficiency of the temperate maize testers also showed that two testers B73 and MO17 were highly efficient in selecting superior line derived from tropical and subtropical CIMMYT germplasm.

The results of the current study showed that it is possible to use maize germplasms from tropical and subtropical regions of CYMMIT to improve grain yield in temperate regions. Also, one temperate maize tester has the ability to distinguish superior sources (not all of them), although the use of two testers greatly reduces the risk of not choosing (deleion) a superior source.

Heterosis, i.e. hybrid vigor, is a commonly observed biological phenomenon used in crop production. The use of heterosis has greatly improved the productivity of cotton worldwide. Knowing the degree of heterosis, either relative to the parent (mean parent or better) or to the commercial control parent, is important in assessing whether hybrids outperform existing varieties. This information can influence the decision to invest in hybrid development. This research was conducted to estimate the effects of genes, heritability, and heterosis to determine the appropriate breeding methods to improve fiber quality and performance parameters and to determine the most efficient method of heterotic grouping for line classification.  In this study, seven maternal genotypes and three paternal genotypes of cotton from different heterotypic groups were crossed in the 2020 crop year in a North Carolina design (II). Three sets of hybrids produced along with their parents were grown in a baseline design of randomized complete blocks with four replicates at the National Cotton Research Institute's Hashemabad Research Station experimental field.  Analysis of the variance of the qualitative and quantitative parameters of the fibers showed that the effect of females, the effect of males, and the interaction between males and females were significant for all parameters except uniformity. The study of genetic parameters showed that the qualitative traits were affected by the additive and non-additive effects of genes. The proportion of non-additive effects in the genetic control of uniformity was higher than the additive effects, while for micronaire strength and 25% fiber length, the proportion of additive effects was higher. The high values of the narrow heritability estimates indicate that the occurrence of qualitative parameters is more influenced by genetic effects. Given the presence of additive effects and low estimates of narrow heritability for the trait kail proportion, it is promising to use breeding programs based on crosses to improve this trait. For other qualitative parameters, estimates of narrow heritability were high. Therefore, the use of breeding programs based on selection to improve these traits is promising. Examination of relative heterosis based on average parents showed that the range of heterosis was from -2.73 to 7.87%1, from 4.52 to 22.23%, from -0.05 to 4.32%, and from 1.25 to 55. For each of the micronaire, strength, elongation, and fiber quality index attributes, the heterosis was 6%.  These results show that since both additive and non-additive effects are involved in controlling fiber quality, it is possible to increase the possibility of collecting suitable additive genes and exploiting variance by choosing an appropriate breeding method such as periodic selection. It provided dominance. These results provide a basis for accelerating the development of hybrids with high fiber quality in cotton.

Obtaining genetic information on how to control traits and becoming aware of the genetic potential of breeding populations is the most important prerequisite for success in cultivar breeding projects. Graphic analysis of the data obtained from the diallel design by means of the (GGE biplot) biplot method allows the breeders to obtain a larger volume of comprehensive genetic information with higher resolution than the conventional methods. The aim of this study was to obtain genetic information and create various breeding materials with high potential in terms of grain yield and its components in bread wheat.

This study started with identifying and collecting 10 bread wheat cultivars with various and complementary characteristics in terms of grain yield and other related and important economic and agronomic traits. The crossing of parental cultivars and the evaluation of the progeny diallel crosses were carried out in 2018 and 2019, respectively. The progenies of the 10×10 full diallel were studied in a randomized complete block design with three replications and examined for grain yield, 1000-seed weight, plant height, spike length, number of seeds per spike and spike weight.

Based on the results of analysis of variance, the mean squares of genotypes were significant for all traits (α≤ 1%), indicating the existence of sufficient diversity among the studied genotypes. Effects of general combining ability for the parents on plant height, spike length, 1000-seed weight and grain yield and effects of specific combining ability for crosses on plant height, spike length, number of seeds per spike and grain yield was significant. Also, the difference of reciprocal crosses was significant for plant height, spike length, number of seeds per spike and 1000-seed weight. The results of bioplot analysis showed that Ehsan had the highest general combining ability among the parents for grain yield, 1000-seed weight, plant height, spike length. Accordingly, the highest specific combining ability for grain yield was observed between Ehsan against both Gonbad and Shoush cultivars. Also, the spesific combining ability of Ehsan in crosses to Kalateh, Barat, Shoush, Sirvan and Gonbad cultivars had the highest value for 1000-seed weight, plant height, spike length and spike weight. The highest narrow sense heritability was observed for spike length however, for plant height, number of seeds per spike, grain yield, 100-seed weight and flag leaf area, the narrow sense heritability was low.

In general, cultivars Ehsan and Gonbad were able to transfer most of the characteristics to their offspring, therefore they can be used in breeding programs to improve grain yield and yield components in bread wheat. Due to the greater importance of the dominance component in control of grain yield and its components, can be used to determine suitable parents for crossbreeding and production of new varieties.

Coriander (Coriandrum sativum L.) is an annual herb of the umbel family and is belonged from North Africa to south-western of Asia. Coriander is one of the important medicinal plant that used in the pharmaceutical industry and it mainly cultivated and widely distributed for the fruits. The dried fruits are widely employed as a condiment, especially for flavoring of sauces, meat products and bakery and confectionery items. Also, coriander fruits are as a source of essential oils and fatty oil. Water deficit stress is one of the most important factors limiting the growth and survival of plants in arid and semi-arid regions of the world. Water is a major component of the fresh produce and significantly effects on weight and quality of plants. Also, water deficit may cause significant changes in the yield and composition of essential oils in aromatic and medicine plants. So that, was reported that water deficit increased essential oil percentage in coriander but decreased essential oil yield. Iran with an average annual rainfall of 240 mm is included among arid and semi-arid regions of the world. Of the million hectares of cultivated region, only five millions are under irrigation because of intense water limitations. However, Iran is one of the world’s commercial coriander producers. Coriander has been cultivated for many years in different parts of Iran. Therefore, development of drought-tolerant cultivars with high essential oil yield is important in coriander. The objective of this study was evaluation general combination ability of endemic coriander genotypes for fruit yield, yield components and essential oil content under different watering regimes.

F14 half sib families including TN-59-10, TN-59-36, TN-59-80, TN-59-158, TN-59-160, TN-59-164, TN-59-230, TN-59-306, TN-59-347, TN-59-353, TN-59-357, TN-59-422, TN-59-450 and commercial genotype were evaluated in randomized complete block design with three replications in each experiment during growing season of 2016 in the research field of Tarbiat Modares University. Plants were treated with different levels of water treatment: well watered (WW), moderate water stress (MWS) and severe water stress (SWS).

Results of data analysis revealed that total chlorophyll (86.32%), fruit yield (98.56%) and essential oil content (48.85%) exhibited the most phenotypic coefficients of variation in non-stress, moderate stress and severe stress conditions, respectively. Also, the most genotypic coefficients of variation in non-stress, moderate stress and severe stress estimated for essential oil content (79.86%), fruit yield (43.76%) and essential oil content (45.5%) respectively. Results of cluster analysis using general combining ability (GCA) data revealed that F8, F9, F10 and F14 are suitable for synthetic variety production to cultivate in full irrigated condition because these genotypes had high GCA for fruit yield and its component. F1, F7 and F11 are suitable to produce high fruit and essential oil yielding variety in moderate drought stress. Also, F6, F7, F11, F13 and F14 suggested as donor for fruit yield and F1, F3, F7, F9 and F12 for essential oil content in severe drought stress.

Generally, the results indicated that that F8, F9, F10 and F14 are suitable for synthetic variety production to cultivate in full irrigated condition because these genotypes had high GCA for fruit yield and its component. F1, F7 and F11 are suitable to produce high fruit and essential oil yielding variety in moderate drought stress. Also, F6, F7, F11, F13 and F14 suggested as donor for fruit yield and F1, F3, F7, F9 and F12 for essential oil content in severe drought stress.

To estimate general and specific combining abilities and heritability in potato genotypes diallel analysis based on Griffing method was used. Reciprocal crosses were made between four commercial potato cultivars; Savalan, Luca, Satina and Caeser parents. For crosses and preliminary tuber seed increase carried out at greenhouse, and main gentypic evaluation trial was performed in field at Alarouq research field station during 2016-2019. There were significant differences between genotypes for tuber yield, tuber number and weight plant-1, main stem number plant-1, plant height, mean of main stem diameter, and tuber dry matter content. General and specific combining ability of tuber yield, tuber weight per plant and plant height were significant. The highest positive and significant general combining abilities for tuber yield, tuber weight plant-1 and main stem number plant-1 belonged to cv. Luca and cv. Savalan. The highest positive and significant specific combining ability for tuber yield was observed for ♂Savalan×♀Luca, ♂Satina×♀Luca, ♂Caeser×♀Luca, ♂Caeser×♀Savalan, ♂Luca×♀Caeser and ♂Savalan×♀Caeser. Tuber yield, tuber weight plant-1, plant height, main stem number plant-1 and tuber dry matter content had higher general heritability.

To achieving favorable outcomes in breeding programs, parental selection based on General combining ability (GCA) and Specific combining ability (SCA) is important. In order to investigate the genetically characteristics and general combining ability and specific combining ability and disease-resistant genes action against take-all in bread wheat, 6 wheat genotypes (729, 1622, 2109, 1528, 1546, 1526) were crossed in One-way diallelcross. Seeds of crosses (F1s) and parents were planted in the research greenhouse of Vali-e-Asr University of Rafsanjan. the take-all disease tolerance, stem dry weight, root dry weight, tiller number and Mn, Zn, k and Fe concentrations Were measured. Griffing analysis showed that general combining and specific combining ability were significant for all traits except for tiller number and iron element. The best general combiner in viewpoint of take-all resistance were 1622 and 729. The best hybrids in viewpoint of disease resistant were 2109×1546, 546×1528 and 1622×1526 that has the highest specific combining ability. Evaluation of genetic parameters by Hayman method for disease index and disease score confirmed the results of griffing analysis and showed that the dominance and over dominance of gene’s actions have the greatest importance in genetic control of the resistance to take-all disease (T-41 isolation). Finally, due to low specific heritability and low genetic ratio in resistance to take-all disease, it can be said that this trait do not respond well in early generations so selection after purity can be effective and can be done by bulk, single-seed descent and double haploid methods in wheat breeding.

To estimate general combining ability (GCA), specific combining ability (SCA) and genes action in sesame, a 7×7 diallel cross was conducted using randomized complete block design with three replications under non-stress and stress conditions in 2005 and 2006 in research field of faculty of agriculture of Birjand university. Analysis of variance showed significant differences between genotypes. Griffing analysis showed that significant GCA for all traits in non-stress and stress conditions. SCA was significant for all traits, except plant height, height to first capsule and number of capsule, in non-stress conditions. In stress conditions, SCA was also significant for all traits, except plant height, auxiliary branch number and number of capsule plant-1. Hayman analysis of variance showed that additive genetic variance was significant for all traits in both conditions. The dominant genetic variance was significant for all traits, except plant height and height to first capsule, in non-stress conditions. It was also significant for all traits, except plant height, in stress conditions. Inheritance of yield and related traits was relatively high in both conditions. Broad sense heritability varied from 0.51 (plant height) to 0.99 (several traits), and narrow sense heritability varied from 0.27 (harvest index) to 0.99 (number of capsule) in both conditions. The highest (29.2%) and lowest (-9.47%) heterosis relative to mid-parent observed for grain yield in non-stress and harvest index in stress conditions, respectively. The estimated heterosis relative to superior parent was positive (0.03%) only for capsule length in non-stress conditions.

In order to estimate genetical parameters, general and specific combining ability of bread wheat to determine proper parents for crossing and producing new cultivars, six promised lines planted in randomized complete block design with three replications, in 2017-18 cropping and varieties including, Falat, Mehergan, Ehsan, Sistan, Bam and N-80-19 were planted in Eraghi Mohalle (Gorgan) station in 2016-17 cropping season. A full diallel mating among six parents for generating F1 progenies were done. Sixparental genotypes and 30 F1 progenies were season. The results revealed that cultivar Ehsan was the best general combiner for hundred grain weight. Cultivar Ehsan and Line N-80-19 had the highest general combining ability for grain yield and biomass, respectively. Therefore, it is recommended that these genotypes can be applied in hybridization to increase grain yield and biomass. Additive variance of traits including plant height, peduncle length, grain weight in spike and hundred grain weight was more than dominance variance. Furthermore, Ehsan cultivar had the highest general combining ability (GCA) for grain yield and biomass and hybrids raised from 2×3 (Ehsan×Mehrgan) cross had the highest specific combining ability (SCA) for grain yield and biomass.

Pearl Millet (Pennisetum glaucum L.) is one of the most important crops in arid and semi-arid regions that is cultivated for grain and forage. Due to cross pollination and high heterosis, selection of parents based on combining ability is one of the most important steps in pearl millet breeding programs. To study the general combining ability (GCA) of pearl millet lines, a set of 10 lines were crossed in polycross nursery and the resulting half-sib families (HS) along with a check variety were evaluated in a randomized complete block design with four replications. The studued traits included days to flowering, plant height, stem diameter, number of leaves, number of tillers, fresh forage yield and dry matter. The results of analysis of variance and comparison of means showed that there was considerable genetic diversity for the studied traits. Estimated heritability ranged from 53.86% for dry forage yield to 99.23% for number of tillers. These results showed that additive variance had a significant role in controlling the studied traits in this population and therefore it can be used in breeding programs. Combining ability showed that line 2 for days to flowering, plant height and number of leaves, line 3 for stem diameter, lines 4, 7 and 8 for number of tillers and line 7 for fresh forage and dry matter yield were the best general combiner and could be used as the parents of crosses to improve the studied population.

Wheat is attacked by many pathogens during the growing season, including rust. The causative agent of fungal wheat brown rust called Puccinia recondita f. sp. is also known as leaf rust. The most important way to control brown rust disease is to use resistant cultivars that effectively control and reduce its damage. The most important way to control brown rust disease is to use resistant cultivars that effectively control and reduce its damage. The aim of this study was to investigate the inheritance of brown rust resistance in different wheat cultivars and estimation of genetic parameters using diallel crossing.

Six bread wheat cultivars including Gonbad, Shiroudi, Darya, Atrak and Moghan 3 genotypes with susceptible Bolani cultivar and 15 F1 progenies from one-way diallel crosses were studied. his study was conducted as a randomized complete block design with three replications in field and greenhouse conditions. Traits included infection type, severity of infection, area under disease progression curve and incubation period. Data analysis was performed using SAS ver 9.1 and Excel software and estimation of genetic parameters and heritability of traits were studied by diallel analysis using Griffing's second method with fixed model and Jinks and Hayman method.

Analysis of variance showed that there was a significant difference among genotypes for all traits, indicating genetic variation for these traits and thus genetic analysis could be performed. The mean squares of general and private combining ability were significant for all traits, indicating the importance of both enhancing effects and dominance of genes in inheriting these traits. The Baker ratio indicated the same importance of additive effects and dominance for the incubation period and for the other traits indicated greater importance of additive effects. Estimation of genetic parameters by Jinks and Hayman method showed that for all four traits, the amount of D component was lower than the dominance components (H1 and H2), indicating that the dominance component was more important than the additive component in controlling these traits. The sign of F was positive for all traits, so the frequency of dominant alleles was higher than that of recessive alleles. Wr-vr statistic was significant for all studied traits, indicating the presence of inorganic effects (epistasis). In other words, the significance of this statistic indicates the inaccuracy of the additive-dominance model for traits.

Based on the traits evaluated in field, Atrak cultivar and in greenhouse, Gonbad cultivar had good resistance to brown rust. Narrow-sense heritability of traits was estimated to be between 51 and 86%. Estimation of genetic parameters showed that additive-dominance model was not sufficient. In other words, at least resistance is predictable in resistant cultivars.

Five CMS lines and four restorer lines (tester) were crossed in a line × tester scheme in order to analyze general and specific combining abilities and gene effects in sunflower for some agronomic traits. Hybrids were evaluated in a randomized complete block design, with three replications under optimum and limited water conditions in the Agriculture Research Station, Khoy, during 2015 and 2016 growing seasons. Plant height, head diameter, seeds per head, days to beginning of flowering, days to maturity, proline percent, protein percent, and Chlorophyll b were found to be controlled mainly by dominance effects. CMS lines AGK30 and testers RGHK25 and RGHK50 turned out to be the best general combiners for seed and oil yield. The highest positive and significant GCA for plant height, head diameter, and the number of seeds per head were achieved for RGHK25. The hybrid combination of AGK44 × RGHK56 showed high specific combining ability for seed and oil yield. In the study of general combining ability, the AGK110 line has a positive and consistent general combining ability, and AGK2 has a negative and significant general combining ability with catalase . In the test of the testers, the tester (RGHK50) had the highest GCA positive and meaningful drug tester (RGHK56), which had a significant negative and significant combining ability with catalase . In the study of hybrid hybrid combining ability (RGHK46 × AGK260), the highest positive and significant positive and significant hybrid confinement (RGHK46 × AGK44) had the highest SCA negative and significant levels. In the RGHK46 × AGK260 hybrid combinability study, the highest positive and significant positive and significant hybrid confinement (RGHK46 × AGK44) had the highest SCA negative and significant effect on catalase identity. The AGK44 line has the ability to combine publicly and positively with AGK110 capability. The general combining ability was negative and significant with SOD. In the test of the testers, the RGHK 56 tester had the highest GCA positive and significant mean of the RGHK25 tester, which had a negative and significant general combining ability with superoxide dismutase. In the study of hybrid hybrid combining ability (RGHK50 × AGK260), the highest positive and significant positive and significant positive combining ability (RGHK50 × AGK44) had the highest SCA negative and significant values for SOD. In explaining the traits, plant height, Number of seeds per head and percentage of proline under stress conditions played a more significant role. Plant height and number of seeds per head were controlled by both growth and dominance effects. also In the study of general combining ability, the highest GCA positive and significant values were related to the AGK30 line and the most general negative and significant general combining ability was AGK2 line (Table 4-14). In the test of the testers, the tester (RGHK 46) had the highest GCA positive The drug tester (RGHK25) had the most significant negative and significant general combining ability with proline). In the study of hybrid combining ability (RGHK46 × AGK2), the highest positive and significant positive and significant hybrid confinement (RGHK25 × AGK260) had the highest SCA negative and significant values .

Improvement of forage quality is one of the important purposes of alfalfa breeding in order to develop cultivars with higher feeding values. The objective of this experiment was to evaluate of combining ability and heterosis for forage quality including; leaf to stem ratio, crude protein, soluble carbohydrate, ash, acid detergent fiber and neutral detergent fiber by GGE biplot graphical method. Selected partially inbred lines from the second generation selfing of eight alfalfa ecotypes were evaluated in a half-diallel cross design. Field experiments were performed in a randomized complete block design with three replications, included eight parents and 28 F1 at two locations, Karaj and Arak, Iran, during 2015-2016. Based on the results of Griffing method, mean square of GCA and SCA and SCA by environment interaction were significant for all the traits (p<0.01) and GCA by environment interaction were significant for leaf to stem ratio (p<0.05) and also for ADF and NDF (p<0.01). GGE biplot graphical method showed the highest positive GCA for Silvana and the most negative GCA for Kozare and Rahnani for leaf to stem ratio, crude protein, soluble carbohydrate, ash. Nikshahri showed the highest positive GCA for acid detergent fiber and neutral detergent fiber as the unfavorable traits. SCA was the maximum for two specific parents; Ghahavand and Silvana for all the traits. Results revealed that there were proper diversity and heterosis for forage quality in alfalfa parents, so selfing and crossing between the partially inbreds (S2) could be possible by crossing between best single crosses to produce free hybrids to improve forage quality.

Heterotic groups distinguished among breeding populations provide basic information to help plant breeders to control heterosis consciously. Development of alfalfa free hybrids can provide heterosis through parents' selection with crossing between partially inbred lines from two or three generations of selfing. In order to study of combining ability for forage dry matter, height and regrowth rate, selected partially inbred lines from the second generation of eight ecotypes of alfalfa were evaluated in a half-diallel cross design. Field experiments were performed in a randomized complete block design with three replications, including eight parents and 28 hybrids (F1) at Karaj and Arak during 2014-2015. Graphical GGE biplot method was applied to analyze the data. Based on the results of analysis of variance, mean square of GCA and SCA, and their interaction with environment were significant(p<0.01). GGE biplot graphical method showed the highest positive GCA for Nikshahri and the highest amount of negative GCA for Kowzareh and Rahnani as parents of crosses for all traits. SCA was maximum for two specific parents, Nikshahri × Ghahavand and Nikshahri × Silvana crosses. Results also indicated that crossing between the Iranian partially inbreds (S2) of alfalfa to produce free hybrids can provide opportunities to exploit heterosis potential and improve forage yields.

Six rainfed durum wheat genotypes (Chehel daneh, Gerdish, Zardak, Syrian-1, Waha and Knd1149//68/ward) and their complete diallel progenies of F1 generation were evaluted in a randomized complete block design with two replications. Analysis of variance indicated genetic differences among genotypes. General combining ability (GCA) was significant for all of the studied traits except hundred grain weight (HGW). Specific combining ability (SCA), reciprocal and non-maternal effects were significant for grain yield (GY), HGW and flag leaf area (FLA). The results indicated low values of narrowsense heritability and superiority of dominance effect for plant height (PH), GS, GY, HKW and FLA. The cross of Waha × Knd1149//68/ward with high value of GY and GCA for this trait can be used as a suitable cross for use of heterosis. This cross was also superior to their parents according HGW, NGS and SL. Gerdish can be used as a suitable parent for breeding programs to receive lines with high yield and yield components according to positive and significant GCA for number of spikelets per spike, SL, NGS, GY and FLA. According to predominance of additive effects in genetic control of number of spikelets per spike and spike length, selection can be useful for improvement of these traits, while selection was not applicable in primary generations and should be delayed for the other traits untill advanced generations.

The most important step in developing of a sugar beet hybrid for target trait is selection of CMS line or single cross. In the present study, 12 progenies derived of 4 sugar beet lines(as female parent) with different level of rhizomania resistant, along with 3 pollinators 27270, 27273 and 27274(as male parent) and parents were evaluated in two locations (Mashhad and Shiraz) with rhizomania infestation in 5×5 latice design with 4 replications. The traits consisted of: Root yield (RY), sugar yield (SY), sugar content (SC), Na, K, N- , white sugar content (WSC), purity (PUR) and molas percent (MS). The data analyzed as factorial model in randomized complete block design. The results of genetic analyses in two locations showed significant differences among parents for all the traits except for K and N- . Variance of hybrid was significant for RY and SY. In Mashhad experiment L3 line and T3 pollinator and in Shiraz experiment L3 and L1 lines and T3 pollinator were selected as superior parents for RY, SY and N- traits. The value of SCA showed that in Mashhad experiment L1×T3, L2×T2, L3×T1 and L4×T1 crosses and in Shiraz experiment L1×T1, L2×T3 and L1×T3 had significant and positive value of SCA for RY and SY. As a total, the results showed that cross between a rhizomania susceptible single cross (L1) with a resistant pollinator (T3) was the best sugar beet hybrid among them.

Maize germplasm from CIMMYT is genetically most diverse in the world and is exceedingly useful for broadening the genetic base of temperate maize germplasm. It is a tough challenge for improving efficiency and reliability of extracting the best suitable material from exotic germplasm. So, this study was done to determine the optimum number of testers and suitable testers for screening a maize line derived from tropical and subtropical CIMMYT germplasm. For this purpose, four temperate maize testers (MO17, K18, K166B and A679) with thirteen lines originated from CIMMYT germplasm were crossed. Resulted fifty five crosses along with two hybrid checks were evaluated using a randomized complete block design with three replications at Moghan. The results indicate that there was the possibility of direct use of lines No 3, 5 and 7 derived from tropical and subtropical CIMMYT germplasm to improve grain yield. The performance of the temperate maize tester showed that tester K166B had high efficiency in selecting superior line derived from tropical and subtropical CIMMYT germplasm and testers MO17 and A679 were relatively good. Results revealed that one inbred line tester would effectively select most, if not all, of the top best exotic lines and two testers gave more reliable results than one tester did.

IntroductionDiallel crosses can be used to study the gene action and heterotic grouping and patterns. In the recent decade, use of graphical approach or GGE biplot in the investigation of genotype × environment has become more common in breeding programs. In this method, the effect of genotype and genotype and environment interaction are broken and stable cultivar selection is done basis of both effects. When GGE biplot was used for diallel data, each genotype reviled as both line and tester. Also in this case, average performance and stability of genotypes equivalent with the parent GCA and SCA respectively. Biplot method very useful tool for visual assessment and interpretation of the parent’s pattern, the environment and their interaction. The aim of this study provides the following information for wheat base graphical (1) Set parental general combining ability, (2) Estimates specific combining ability for hybrids, (3) Determine the adequate testers for future research, (4) Determine the best hybrids, (5) Determine of heterotic group and patterns among genotypes.
Materials and MethodsIn this study, seven varieties of wheat including Alamut, C-84-12, Gaspard, Ghods, Moghan 1 and Afshar (as parents) were used. These varieties with 21 genotypes of F1 generation of them base half diallel (without reciprocal crosses) in 2012-2013 crop year on research farm of Agriculture and Natural Resources, Islamic Azad University of Karaj, in drought stress condition were cultivated. A randomized complete block design with three replications was used. To analysis of variance SAS software and for Diallel analysis D2 software were used. Graphical analysis according to Yan and Hunt method done with GGE biplot software. In order to evaluate the diallel results in bread wheat, biplot method was used. In this study, 12 agronomic traits, including Grain yield, Plant height, Spike length, Spike Weight, Stem diameter length, Awn length of the second internodes, Peduncle length, Extrusion peduncle, Seed length, Seed size and 1000 Seedweight were examined.
Results and discussionAnalysis of variance showed significant differences for most of the traits. General combining ability mean squares for all the traits except plant height, length of the second internodes and stem diameter was significant. Specific combining ability mean squares for all traits except stem diameter was significant at the one percent probability level. The highest and lowest average grain yield for parents was observed for Hamoon and Afshar cultivars and for hybrids observed for crosses the Hamoon × Ghods and C-84-12 × Gaspard. The most significant positive GCA for grain yield, was reviled for Hamoon variety. The most significant SCA for grain yield per square meter, observed for Hamoon × Ghods and C-84-12 × Moghan1. For spike weight, the highest and significant SCA values observed for Afshar × C-84-12 and Alamut × Gaspard. For grain weight the highest SCA observed for Alamoot × Ghods and Afshar × C-84-12. For spike length, Alamoot × C-84-12, Ghods × C-84-12, Afshar × Gaspard and Ghods × Moghan1 had a positive and significant SCA. Based on the results of diallel analysis biplot for grain yield of the lines, Cultivars Alamut and Afshar respectively, have a highest and lowest general combining abillity. Cultivars C-84-12, Ghods, and Gaspard has a specific combining ability were higher than other lines. Cultivars were divided into two groups. The first group includes Cultivars Gaspard, C-84-12 and Hamun, second group includes Alamut, Ghods, Moghan1 and Afshar. Testers Ghods, Alamut, C-84-12 and Gaspard similarities and relationships more than other tester for grain yield. Cultivars Ghods, C-84-12 and Alamut had more discriminating effect than other varieties.
ConclusionsIn total, there were significant genetics diversity between cultivars that cause of the additive and non-additive effects in the studied traits such as yield. Comparing the results of numerical analyzes with graphical results represents the good conformity between of these two methods. Due to preferable of graphical methods in terms of faster and simpler interpretation for results, the use of these methods, to facilitate the investigation, recommended.

GGE biplot method is one of the appropriate methods for analyzing the data with bilateral structure. In the present research, the GGE biplot model was used to identify promising heterotic crosses for paste viscosity parameters in rice (Oryza sativa L.) by using 8×8 full diallel progenies. In direct crosses, parents Deylamani, RI1843046, IR50 and RI184421 were identified as good general combiners for peak viscosity, while in reciprocal crosses, only parent RI184421 was the best combiner for this trait. The parents RI1843046 and RI184421 for breakdown viscosity property and the parents BC4, Deylamani and Tarommahalli for final viscosity parameter were identified as good general combiners in direct crosses, but RI1843046 was the best general combiner for both trait in reciprocal crosses. Although, the parents BC4 and RI184421 were respectively the best general combiners for setback viscosity in direct and reciprocal crosses, but the parent Deylamani was good general combiner for this trait in progenies of both cross. The results of this research showed that the crosses RI1843046 × RI184472, RI184472 × Deylamani and Deylamani × IR50 for peak viscosity, RI1843046 × Line 23, RI184472 × Deylamani and RI184472 × Tarommohali for breakdown viscosity, RI1843046 × RI184472 and RI184421 × IR50 for final viscosity and BC4 × RI1843046 and Deylamani × Line 23 for setback viscosity were the best specific combiners. The good general combiners to organize a new population and the good specific combiners as the suitable heterotic combinations for producing the progenies with suitable paste viscosity properties are suggested.

This research was conducted to evaluate genetic variation and estimate genetic parameters of forage yield and related traits in Dactylis glomerata. Twenty five half sib families derived from poly cross of 25 parental genotypes were evaluated under two moisture environments (normal and drought conditions) according to a randomized complete block design in Research Farm of Isfahan University of Technology. Results indicated that there are significant statistical differences and high genetic variation among the families for most of the studied traits. Drought stress significantly affected all forage related traits (except for leaf to stem ratio), leading to decreases in a majority of them. Mean of forage yield was decreased by 53.48 percent due to drought stress. Genotypic coefficient of variation under non-stress condition ranged from 1.78 to 45.1 and under drought condition ranged from 1.7 to 30.4, indicating a high genetic variation in this germplasm. The highest narrow sense heritability was related to crown diameter in both moisture environments. Narrow sense heritability for dry forage yield was 52% at non-stress and 45% at stress conditions. Based on dry forage yield, genotypes 2, 5, 8, 13 and 15 showed a higher general combining ability in both moisture conditions and, therefore, are potent to be used for developing synthetic varieties.

One hundred maize new hybrid combinations of four testers with 25 inbred lines were evaluated using randomized complete block design with three replications in 2013 over four locations، Karaj، Dezful، Kermanshah and Jiroft، Iran. Based on the results، hybrids KSC 715، KSC 703، K47/2-2 × MO17، K47/21 × MO17 and K47/2-2 × K166B produced the highest grain yield، (13. 100، 13. 070، 12. 610، 11. 890 and 11. 810 tha-1)، respectively compared to the check hybrids. Combined analysis of line × tester revealed significant effects of lines and line × tester interaction، meaning variability among lines، as well as role of additive and nonaddtitive gene effects in heritability of grain yield. Line K47/3 was identified as a the best general combiner، which could be used as suitable tester in the future programs.