Identification of quantitative trait loci for panicle length and yield related traits under different water and P application conditions in tropical region in rice (Oryza sativa L.)
Ian Paul Navea,Maria Stefanie Dwiyanti,Jonghwa Park,Baccki Kim,Sangbum Lee,Xing Huang,Hee-Jong Koh,Joong Hyoun Chin
Plant Breeding, Genetics, and Biotechnology Division,International Rice Research Institute, Los Banos,Philippines
Abstract: Climate change is projected to have a serious impact on the yield potential of rice in tropical as well as in temperate countries. It is therefore essential to develop rice varieties which are climate change ready and with stable yield when grown under low inputs of irrigation water and fertilizer. In this study, the effects of the shift from temperate to tropical environment as well as the different levels of water regime-phosphorus application were evaluated using a set of temperate recombinant inbred lines (RILs) derived from a cross between Dasanbyeo (Tongil-type indica) and TR22183 (temperate japonica). Here, we have identified genetic mechanisms for yield stability mainly by observing the panicle length in the RILs and the parental lines. TR22183 grown in the Philippines showed no reduction in panicle length whereas the Dasanbyeo exhibited a considerable reduction in panicle length when grown in the Philippines compared to those grown in Korea. In the RILs, a total of 18 QTLs for panicle length were identified across 12 chromosomes except in chromosomes 6 and 7. There were six interesting panicle length QTLs, qPL1.4, qPL2.1, qPL2.2, qPL4.1, qPL9.2, and qPL11.2 on chromosomes 1, 2, 4, 9, and 11 respectively. They were clustered together with other yield-related QTLs such as spikelet number and grain number in two different years. Except for qPL2.1, all the beneficial alleles originated from TR22183. The panicle length QTLs were identified across different water-P treatments. Interestingly, qPL1.4, qPL2.1, qPL4.1, and qPL11.2 were constantly detected in the low-input tropical condition. No QTL for panicle length was identified in the parallel experiment conducted under temperate conditions in Korea suggesting that the QTLs identified in tropical conditions could be useful in breeding programs to develop rice varieties that have stable yield potential under a warming temperate climate.
Keywords: Climate change;Phosphorus;Panicle length;Yield;QTL;EpQTL;SNP