نشریه تولیدات گیاهی
سال سی و ششم شماره 2 (تابستان 1392)

Mango is one of the tropical crops cultivated in the south of Iran, where it has fewer yields in comparison with other regions of its cultivation. According to reports, cross pollination will increase the yield of this plant. The objective of this study was to compare the effects of selfing, control crossing and open pollination on pollen tube growth and fruit setting in three cultivated mango genotypes in Iran. The inflorescences in some trees were bagged after related pollination treatment. Sampling was done from the pollinated flowers three and seven days after pollination. Pistils were stained with aniline blue and the situation of pollen tube growth was studied using a fluorescence microscope. The final fruit production was counted 15 and 90 days. After pollination, mean fruit length, width, weight and TSS were recorded in all treatments. In all genotypes, selfing inflorescence prevented fruit set completely. There was significant difference in pollen tube growth and fruit set of self crossing and open crossing treatments. The maximum fruit set was observed in genotypes one and three with pollen grain of genotype two. The results of this study showed that the source of pollen can influence quantity and quality characteristics of mango, so much so that self-pollination usually results in significantly lower crop production than cross-pollination in mango. In addition to higher production of controlled cross pollination with cross pollen grain, the selection of proper parent plants should be done with sufficient care in order to improve production efficiency in this crop.

The selection of high performance varieties with high stability is an important objective for canola breeding programs in rain-fed and arid areas. Also, evaluation of G×E interaction is very important for releasing stable varieties in different regions. In this research, the stability and adaptability of 19 advanced lines of canola for grain yield were compared in Gachsaran (semi-warm and dry area) experimental station during 2005 to 2007 cropping seasons. The experimental design in all three years was randomized completely block design with three replications. Combined analysis of variance showed that the effect of variety and year × variety interaction were significant. The different stability methods were used to identify stable genotypes in this research. These methods were parametric including, type I parameters (Environmental variance (S2i), Coefficient of variation (C. V.)), type II parameters (Shukla stability of variance and Wrick equivalence indices, regression (bi)), type III parameters (Deviation of regression (S2di), and Non-parametric method of rank (based on R and SDR parameters). Finally, genotypes Option 500، PP-308-8، PP-401-15E، PP-401-16 and Shiralee with high stability and grain and oil yields were selected and introduced as the most stable cultivars with high oil yield.

This experiment investigated the effects of different levels of vermicompost and plant density on growth and developmental factors, seed yield and oil content of evening primrose (Oenothera biennis L.). The research was set up as a factorial experiment on the basis of Randomised Complete Block Design (RCBD) with three replications in the experimental field of the Agricultural faculty of Ferdowsi University of Mashhad (FUM) during 2008-2009. The treatments included 4 levels of vermicompost (0, 2, 3 and 5 kg.m-2) and 3 levels of plant density (9, 12 and 20 pl.m-2). During the flowering period, plant height, number of side branches, number of capsules and seeds per capsule at main stem and side branches were measured separately. The oil of the seeds was extracted by using Soxhlet. The results showed that the simple effects of vermicompost and plant density were significant on the number of capsules and seeds per capsule of the main stem and side branches, as well as oil yield. The highest plant height and oil yield were obtained at the highest level of vermicompost, and the highest number of seeds per capsule of the main stem and side branches were obtained at average levels of vermicompost (3 and 5 kg.m-2). Increasing the plant density decreased the number of side branches, capsules and seeds per capsule of the main stem and side branches significantly. However highest oil yield obtained in the highest level of plant density. There was a significant interaction effect between vermicompost and plant density on the number of side branches, the number of seeds per capsule of the main stem and side branches.

This study was conducted to evaluate the interaction of urban treated sewage and nitrogen fertilizer on yield and forage production of sweet corn in research farm of Yasouj, during agronomic year of 2008-2009. Experimental factors consisted of 5 irrigation levels including common irrigation water from emergence (SG=10) to milk stage (SG=82) (I1), from SG=10 to tassling (SG=50) with sewage effluent and from SG=50 to SG=82 with common irrigation water (I2), from SG=10 to SG=50 with common irrigation water and from SG=50 to SG=82 with sewage effluent (I3), alternate irrigation with common irrigation water and sewage effluent till stage (SG=82) (I4), sewage effluent till stage (SG=82) (I5), and 3 nitrogen rates (N0=0, N80= 80 and N160=160 kg N ha-1) in a completely randomized design with three replications. Results indicated that interaction of irrigation and nitrogen was significant on fresh ear yield and canned grain yield. The highest fresh ear and canned grain yield were in treatment I5N80, as 2548 and 1246 gr m-2 and the minimum fresh ear yield and canned grain yield were found in treatment I1N0, as 1090 and 360 gr m-2 respectively. The interaction of irrigation and nitrogen was significant on biological yield and fresh forage yield. The highest biological yield and wet forage yield were obtained in treatment I4N80, 5442 and 2897 gr m-2, respectively. The minimum biological yield and wet forage was in treatment I1N0, as 2953, 1863 and 447 gr m-2 respectively. At I5 Irrigation level, nitrogen consumption was decreased 50%. In summary, application of sewage effluent reduced used nitrogen fertilizer rate.

The effect of different levels of salinity arising from sodium chloride on plant growth parameters, phosphorus, potassium and sodium uptake by saffron plant with and without mycorrhiza was studied in a pot experiment. A factorial experiment with a randomized complete block design was performed. The results showed that increasing salinity from 1.5 to 7.5 dS m-1 significantly decreased plant dry weight. The decreased plant dry weight was attributed to the toxicity resulting from high Na+ concentration and low K+ concentration in plant tissues. Mycorrhizal colonization led to a significant reduction in the concentration of Na+ and improved K+: Na+ ratio,and this in turn, resulted in a considerable increase in plant growth. Percentage of root colonization was not affected by salinity. Despite the reduction of mycorrhizal plant dry weight with increasing salinity, mycorrhizal growth response increased as salinity was increased. Shoot phosphorus concentration and shoot phosphorus content of mycorrhizal plant were significantly higher than those in the shoot of non-mycorrhizal plant. Although shoot phosphorus content decreased with increasing salinity, shoot phosphorus content per unit root length colonized increased as salinity was increased, and this may explain the increased mycorrhizal growth response with increasing salinity. In conclusion, the result of this study, for the first time, showed that saffron has high mycorrhizal dependency, and mycorrhizal colonization alleviated the detrimental effects of salinity on plant growth, uptake of phosphorous and potassium and K+:Na+ ratio.

Many indices have been introduced to compare of tolerance and susceptibility of field crops to environmental stresses. In order to compare spring bread wheat cultivars using indices of tolerance and susceptibility to terminal heat stress, a field experiment was conducted in Ramin University of Agricultural and Natural Resources, Ahvaz in 2007-2009. The experimental design was stripe block in randomized complete block design with three replications. The experimental factors were four sowing dates (6 Nov., 6 Dec., 5 Jan. and 4 Feb.) in horizontal plots and 20 spring wheat cultivars in vertical plots. The results showed that cultivars had a significant effect on the stress susceptibility index (SSI), tolerance index (TI), productivity mean (MP), harmonic mean (HM), yield stability index (YSI), ranking index (Rank), geometric productivity mean (GPM), stress tolerance index (STI), yield stability (YI), modified stress tolerance index for favorable conditions (MSTI1), modified stress tolerance index for unfavorable conditions (MSTI2) and yield reduction percent index (YRPI). Generally, the stress tolerance index (STI) was the best estimate of tolerance and susceptibility of spring bread wheat cultivars to terminal heat stress showing Virinak and Roshan as tolerant and susceptible cultivars, respectively.

The study of biochemical and physiological variations under salinity stress conditions may provide a means to understand effective factors in salinity stress conditions. In order to evaluate the factors that affect salinity, this experiment was conducted in the greenhouse of Shahid Chamran University of Ahvaz during 2008-2009 growing season. This experiment carried out using a factorial test based on completely randomized design with four replications. The first factor (genotype) included Hayola 401, RGS0003, and Shiraly, and the second factor (salinity levels) had three levels of salinity (50, 100 and 150 mM) as well as distilled water as control conditions. Sources of salinity were NaCl and CaCl2 with equal ratio applied until the end of the flowering stage. Salt stress caused decrease of shoot dry weight, osmotic potential, and RWC in all three genotypes. The results showed that total soluble sugars and SPAD value increased in 100 mM but decreased at 150 mM. Under salinity stress, proline content increased along with increasing of salt stress. Shiraly genotype had effective mechanisms to induce tolerance to salinity stress compared to the other studied genotypes. The results of correlation traits indicated that in all three salinity levels, decreasing of total dry weight increased SSI. In 100 mM, RWC showed negative correlation with SSI. There was a negative correlation between proline and osmotic potential in 50 and 100 mM. High accumulation of proline, more total dry matter, and RWC of leaves might be useful criteria for the selection of canola genotypes under salinity stress conditions.

In order to study the effects of different levels of water logging at different growth stages on yield and yield components of barley WB-79-10, a field experiment was carried out using split plot in randomized complete block design with four replications in Ramin Research Field Station in a growing season (2009-2010) in Ramin Agriculture and Natural Resources University, Ahvaz. Tillering, stem elongation and booting stage were assigned to main plots, and water logging periods, including 0, 7 and 14 days in terms of water logging were randomized in sub–plots. The results showed that between the beginning stages of water logging and various water logging periods for yield and yield components, significant differences exist. The water logging at tillering stage had more damage than stem elongation and booting stages on grain yield and its components. In the tillering stage, grain yield at 7 and 14 days, compared to control water logging 42 and 78.28 percent respectively, to the spikelet, respectively 20.84 and 37.5 percent and to the grain number per ear 22.31 and 41.04 percent respectively, decreased. Overall, the results showed that water logging at each stage of plant growth, even in a short period, led to irrecoverable damage on yield and its components on the leaves.

This field experiment was conducted for evaluation of irrigation timing on different fertilizer systems on yield and yield components of wheat (Chamran v.) in 2009-2010. The experiment was performed in RCBD with three replications (split plot design) at Ramin of Agriculture and Natural Resources University. To evaluate the effect of irrigation time the following treatments were applied: cut irrigation I1) from spike formation to harvesting, I2) from anthesis stage to harvesting, and I3) control with complete irrigation. For fertilizer systems, treatments included NPK Chemical NPK chemical sources manure, biological fertilizer and biological and manure. The effect of irrigation timing and fertilizer systems had a significant effect at 1% on remobilization, percent of organic matter remobilization efficiency, seed fraction of remobilization and current photosynthesis. The I3 had minimum remobilization content and maximum current photosynthesis, but I1 treatment had opposite trend. The biological fertilizer together with manure had maximum remobilization and current photosynthesis. Therefore, biological fertilizer together with manure can provide a good condition for high yield production in wheat, even under drought stress at the end of the ripening period.

In order to study the effect of foliar application of zinc and iron on yield quantity and quality of Soybean (Glycine max (L.)) under drought stress, an experiment was carried out as a split plot based on completely randomized block design with three replications. The main factor included four drought stress levels as irrigation after 60, 80, 100, 120 mm evaporation and the sub factor constituted four levels of foliar application as a water, zinc, iron and combined zinc and iron. The results showed that there was a significant interaction between drought stress and foliar application for seed per pod, pod in lateral branches, biological yield and seed yield. The maximum pod per main node stem and seed weight was obtained from the irrigation after 60 mm evaporation and foliar application of combined zinc and iron. Foliar application of zinc and combined zinc and iron had the highest effect on the seed, biological, protein, oil yield and harvest index. Also, foliar application had a significant effect on zinc and iron concentration in seeds and leaves.

Apricot has short storage life and is marketed immediately after harvest. Rapid ripening process and high respiration rate of apricot cause its short cold-storage duration. Harvesting of apricot fruits in suitable time and packing them increase their storage period. This study was carried out to determine the optimum harvest maturity and packing method of apricot fruits to prolong their storage life and decrease its wastes. Split- factorial based on complete randomized block design was used for "Germez shahroud" apricot fruits in three harvesting stages (as main-factor) based on fruit skin color. The first harvest was conducted when skin color had a predominantly green background with yellowish tinges; the second and third harvest coincided with yellow background with greenish tinges and yellow-orange background color of fruits. Fruits were packed in two methods (as sub-factor) including boxes with polyethylene covers and without it. Fruits stored at 0-2 degree centigrade and 85% RH For 0 (control), 7, 14, 21 and 28 days (as sub-factor). After each storage period, fruits were tested for their properties including fruit weight, firmness, total soluble solid, pH and electrical conductivity. Results showed that the optimum harvest time of this cultivar was when the fruit skin color had a predominantly yellow background with greenish tinges. This is synchronous with 75 days after full bloom equal to 1041 growth degree days or 24987 growth degree hours for "Germez shahroud" cultivar. Use of polyethylene packaging prolonged fruit’s storage life. Under these conditions, the fruits of "Germez Shahroud" could be cold-stored with suitable quality until 21 days. Delay in their packing time reduced apricots storage life significantly. Accordingly, with the increase of fruit's cold storage period, fruit firmness reduced but total soluble solid, pH and electrical conductivity of fruit extract increased significantly.