Gene dosage effects of amylose content in rice endosperm

Abstract

Seven indica rice varieties with different amylose contents were crossed in all possible combinations including reciprocals. Single grains of parents and F's were analyzed to determine the dosage effects of genes responsible for different amylose contents. Different genes for amylose content showed differential effects on endosperm appearance and amylose production in the F. A single dose of very low or low amylose gene was not capable of producing amylose to the level of their non-waxy parent in waxy/non-waxy crosses. The effect of one dose of gene for intermediate or high amylose was highly conspicious with relatively less dosage effect. Dosage effects were observed in both waxy/non-waxy and among non-waxy crosses. In general, amylose content increased with increase in gene dosage though not in a linear fashion. Cases where amylose content decreased with increase in dosage for higher amylose have also been observed. The importance of such results in understanding the inheritance pattern of this trait has been discussed.