The Effects of Introgression of the Submergence1 Allele Into Rice Cultivar Ir64 on Post-harvest Seed Dormancy and Longevity

Abstract

Introgressing the Submergence1 (Sub1) allele into chromosome 9 of high-yielding rice (Oryza sativa L.) cultivars introduced the flood-tolerant trait, but this chromosome also includes quantitative trait loci for seed storage survival. Loss in seed dormancy and viability during post-harvest storage were investigated in cvs IR64 and IR64-Sub1 to test if the introgression of Sub1 affected seed longevity. They were grown in the same controlled environment, mature seeds harvested, and ability to germinate monitored during subsequent hermetic storage at 40°C with 13.5-13.9% moisture content. The overlapping patterns of loss in dormancy and loss in viability during storage were quantified well by a multiplicative model, with similar responses in the two near-isogenic cultivars: both showed almost full dormancy initially with complete, similar, loss in dormancy during the first seven days of storage, loss in viability after 43 days, and 50% viability periods (p50) of 26.4-28.1 days. Hence, introgression of the submergence-tolerant allele Sub1A-1 in rice cv. IR64 did not affect seed dormancy or survival after harvest substantially, but duration to flowering was nine days longer and seed yield also greater in cv. IR64-Sub1.