Inheritance of Silicon Uptake Ability in Rice Blast Resistant Varieties

Abstract

Rice blast disease is the most destructive disease to rice plants and can cause a lost in a yield ranging from 50 to 100%. To develop resistant genotypes, it is necessary to determine the source of resistance, the nature of resistance and the mode of gene action that gives resistance to the disease. It is known that Silicon enhances durable resistance to rice blast disease. The rice silicon uptake inheritance can be studied through crossing the high silicon uptake with low silicon uptake genotypes. Seven genotypes were crossed in a full-dialel design, two genotypes having very high silicon uptake ability, two having moderate silicon ability, two having low silicon uptake ability and the last one was having very low silicon ability. The F1 plants were selfed and F2 plants were tested for silicon uptake ability. Then genetic traits of the segregating F2 populations and their parents were analyzed in order to determine the heritability. A high narrow sense coefficient of genetic determination suggested that there was a considerable heritability of resistance for rice blast. The analysis of gene action revealed that additive gene effects contributed more than the non-additive effects for the inheritance of silicon uptake ability as indicated by high Baker’s ratio (above 0.8 and 0.3) for both silicon uptake and water lose respectively. Genotypes, GIZA182 and E20 were found to have the most desirable GCA among the genotypes used in the study.