تجزيه ژنتيكي مقاومت برنج به بلاست برگ با استفاده از طرح داي آلل

Genetic Analysis of Leaf Blast Resistance, Using Diallel Design

Blast disease is considered as the most serious disease of rice throughout the world. To genetically analyse leaf blast resistance, five rice cultivars namely Khazar, Hashemi, Kadoos, Fuji and Rashti were crossed together in the framework of a defective half diallel design. Parents and the resulting lines were cultured in greenhouse in the form of a randomized complete block design. Following inoculation with five blast isolates of: IA-66, IA-38, IA-79, IA-181, and IA-177, such characteristics as number of blast lesions on the leaf, percent of leaf infection area as well as lesion size were evaluated using international standard method for evaluation of blast disease (S.E.S). The results recorded from the analysis of variance indicated that there exist significant differnces among genotypes. The significance of general combining ability, specific combining ability and also the relationship between general and specific combining ability indicated the effect (simultaneous) effect of additive and non- additive gene action (with a greater share going to additive gene action). In the control of these characteristics a dominant gene also plays its role. High narrow and broad sense heritabilities were reported for all these characteristics. Considering the high heritability in these characteristics and the additive effect of the resistance genes, it can be concluded that Khazar, Kadoos and Fuji resulting lines could suitably be used for cultivars for increasing the resistance against the above mentioned blast disease agents.