Kumar Arvind, Raman Anitha, Yadav Shailesh, Verulkar S B, Mandal N P, Singh O N, Swain P, Ram T, Badri Jyothi, Dwivedi J L, Das S P, Singh S K, Singh S P, Kumar Santosh, Jain Abhinav, Chandrababu R, Robin S, Shashidhar H E, Hittalmani S, Satyanarayana P, Venkateshwarlu Challa, Ramayya Janaki, Naik Shilpa, Nayak Swati, Dar Manzoor H, Hossain S M, Henry Amelia, Piepho H P
International Rice Research Institute (IRRI), DAPO Box 7777, Metro Manila, Philippines.
IRRI South Asia Regional Center (ISARC), Varanasi, India.
Field Crops Res. 2021 Jan 1;260:107977. doi: 10.1016/j.fcr.2020.107977.
The complexity of genotype × environment interactions under drought reduces heritability, which determines the effectiveness of selection for drought tolerance and development of drought tolerant varieties. Genetic progress measured through changes in yield performance over time is important in determining the efficiency of breeding programmes in which test cultivars are replaced each year on the assumption that the new cultivars will surpass the older cultivars. The goal of our study was to determine the annual rate of genetic gain for rice grain yield in a drought-prone rainfed system in a series of multi-environment trials conducted from 2005 to 2014 under the Drought Breeding Network of Indian sites in collaboration with the International Rice Research Institute (IRRI). Our results show a positive trend in grain yield with an annual genetic yield increase of about 0.68 % under irrigated control, 0.87 % under moderate reproductive stage drought stress and 1.9 % under severe reproductive stage drought stress due to breeding efforts. The study also demonstrates the effectiveness of direct selection for grain yield under both irrigated control as well as managed drought stress screening to improve yield in typical rainfed systems. IRRI's drought breeding programme has exhibited a significant positive trend in genetic gain for grain yield over the years under both drought stress as well as favorable irrigated control conditions. Several drought tolerant varieties released from the programme have outperformed the currently grown varieties under varied conditions in the rainfed environments on farmers' fields.
干旱条件下基因型与环境互作的复杂性降低了遗传力，而遗传力决定了耐旱性选择的有效性以及耐旱品种的培育。通过产量表现随时间的变化来衡量的遗传进展，对于确定育种计划的效率很重要，在育种计划中，每年都会更换测试品种，前提是新品种将超过旧品种。我们研究的目的是在2005年至2014年期间，与国际水稻研究所（IRRI）合作，在印度干旱育种网络的一系列多环境试验中，确定易旱雨养系统中水稻籽粒产量的年遗传增益率。我们的结果显示，由于育种工作，籽粒产量呈上升趋势，在灌溉对照条件下，年遗传产量增加约0.68%，在生殖期中度干旱胁迫下为0.87%，在生殖期严重干旱胁迫下为1.9%。该研究还证明了在灌溉对照以及可控干旱胁迫筛选条件下直接选择籽粒产量以提高典型雨养系统产量的有效性。多年来，IRRI的干旱育种计划在干旱胁迫以及有利的灌溉对照条件下，籽粒产量的遗传增益都呈现出显著的正向趋势。该计划发布的几个耐旱品种在农民田间雨养环境的不同条件下，表现优于目前种植的品种。
