Inheritance of Amylose Content and Alkali Digestion Pattern of a High-amylose Mutant Rice “Goami 2”

Abstract

Genetic study on amylose content and alkali digestion (AD) pattern of rice grain was conducted using F1, BC1F1 and F2populations of a reciprocal cross between a high-amylose mutant rice cultivar, Goami 2 and its progenitor variety, Ilpumbyeo. F1seeds of reciprocal crosses between Goami 2 and Ilpumbyeo revealed slightly lower level of amylose content compared to that ofthe field. Also, F1 seeds showed ‘spreading’ type of AD pattern similar to the original variety. The seeds of all progenies in BC1F1and F2 populations were distinctly separated into two different grain types, Goami 2 (GA) type (chalky thin, high amylose andswelling AD pattern) and Ilpumbyeo (IP) type (clear thick, low amylose and spreading AD pattern). However, intermediate type ofgrain appearance and AD pattern was not observed in the progenies of segregating populations. F3 seeds from Goami 2/IlpumbyeoF2 plants of low-amylose (IP type) and segregating (Seg) type plants segregated into 7:8 rather than 7:8:1 ratio. This segregationratio also fited to grain chalkiness and alkali digestion (AD) pattern, spreading or swelling type. The chalky thin grain appearance,swelling AD pattern, and high-amylose content of the mutant ‘Goami 2’ were pleiotropically expressed in the progenies of seg-regating populations. The significantly less segregation GA type progenies far from the expected ratio in F2 might be due to theendosperm type of ‘Goami 2’ may be controled by duplicate recessive genes.