جستجوی مقالات مرتبط با کلیدواژه "نحوه توارث" در نشریات گروه "کشاورزی"

to study the inheritance of stripe rust resistance and to estimate the genetic components of resistance in wheat, F1, F2, BC1 and BC2 generations derived from crosses between two resistant cultivars and one susceptible cultivar (Bolani) along with parental lines were evaluated in a randomized complete block design (RCBD) with three replications in greenhouse. The plant materials were inoculated with pathotype 4E0A+ of stripe rust. In all plants, resistance components including latent period and infection type were recorded after appearance of pustules on leaves. Generation mean analysis revealed that additive, dominance and epistasis play major roles in increasing and decreasing of latent period and infection type, respectively. In spite of significant additive effect, dominance effect was more important in controlling these two characteristics. Broad sense heritability and narrow sense heritability estimates for latent period was 0.33 and 0.28 and for infection type was 0.42 and 0.39 respectively

In order to compare of inheritance, combining ability, heterosis and genes action in the genetic control of 1000-kernel weight, grain per spike, grain yield per spike and grain yield per plant in bread wheat genotypes under drought stress conditions, an experiment was conducted on eight genotypes using fixed method 2 of Griffing. Exception mean squares of grain per spike at specific combining ability (SCA), other traits were significant differences for general and specific combining abilities. It states important of inheritance additive and dominance gene effects under drought stress conditions. The GCA/SCA ratio was significant for grain per spike. For exception of grain per spike, non-additive gene effects were more important than additive. It is concluded that genetic improvement of grain per spike under drought stress conditions is possible at early generations by selecting from the best crosses, while selection for another traits is better that delayed until advanced generations and increase of its heritability.

In order to compare of inheritance، combining ability، heterosis and genes action in the genetic control of flag leaf area، leaf relative water content and grain filling rate in bread wheat cultivars under drought stress conditions، a study was conducted on eight cultivars using method 2 in fixed model of Griffing. General combining ability and specific combining ability mean of squares were highly significant for all the traits with the exception of specific combining ability mean of squares for leaf relative water content that designated importance of both additive and dominance gene effects in inheritance of traits studied in drought stress conditions. The general combining ability mean of square/specific combining ability mean of square ratio was not significant for all the traits. The results of this study showed that non-additive genetic effects were found to be more important than additive effects in genetic control of all the traits. In conclusion، genetic improvement of flag leaf area، leaf relative water content and grain filling rate in drought stress conditions at early generations will have low genetic gain. Therefore، selection for improvement of these traits is better that delayed until advanced generations and increase of its heritability.

Gelatinization temperature (GT) and amylose content (AC) are important traits in determination of rice quality. In the present work four rice cultivars namely Sang-e-Tarrom, Gerdeh, IR229 and IRRI2 were utilized in hybridization as parents, for genetic characterization and study inheritance of the related traits. Direct and reciprocal crosses were performed between parents Sang-e-Tarrom and Gerdeh, and IR229 and IRRI2 respectively. Inheritance of the related traits was studied in direct and reciprocal crosses for low and high GT and high and low, intermediate and high AC. For these evaluations only generations P1, P2, F1, F2, BC1, BC2 and their reciprocal crosses were utilized. Results showed that the gene intermediate dominates on low GT and also high amylose content were dominant on low and intermediate. From direct and reciprocal crosses Gerdeh × Sang-e-Tarrom and IR229 × IRRI2 it was shown that GT and AC expressions were under monogenic control of one major gene corresponding with several modifier genes. Gene dose effects play a tremendously important and effective role in segregation production among traits. Based on these results, selections can effectively be performed in later segregation generations for AC and in early generations for GT.

To study the inheritance of grain yield related traits in barley, F1, F2 and F3 generations derived from Afzal x Cwb cross, along with parents were planted in a randomized complete block design with three replications. Spike weight, spike length, number of spikelets per spike, awn length, thousand grain weight, grains per spike and straw yield per spike in different generations were recorded. Generation mean analysis was performed for all the traits. The results showed that additive, dominance and epistasis effects were significant for all the traits except awn length. Results also indicated that dominace variance was the most important in inheritance of all the traits. Average broadsense heritabilities were between 58%-82% for all the traits. The estimated number of genes for the traits were ranged from one to five.

In order to evaluate heritability and gene action for resistance to barley powdery mildew, two resistant cultivars were crossed with a susceptible one. P1, P2, F1, F2 and F3 generations were planted in a Randomized Complete Block Design. At seedling and booting stages, susceptible cultivar was inoculated with a isolate of the pathogen. Infection type and disease severity were recorded and generation mean analysis was performed. The results showed that additive, dominance and epistasis effects were important for the two examined traits. Analysis of generation indicated that dominant variance was more important than additive variance in both traits. The approximate number of genes were estimated to be between one and two.