A PhilRice study on the development of submergence-drought tolerant breeding lines has identified six recombinant inbred lines (RILs) that show good phenotypic traits, high tolerance to submergence and drought stresses, and high grain yield.
According to Jonathan S. Conception, among the study researchers, recombinant lines are products of conventional breeding where two varieties with desirable characteristics are crossed or paired to arrive at desired traits.
Breeding lines were developed from PSB Rc14 and PSB Rc68 after single cross breeding. PSB Rc14 is a drought-tolerant variety whose average yield is 2. 495 t/ha. Average yield of PSB Rc68, a submergence-tolerant variety, is 2.473 t/ha.
Multi-location trials of the RILs were conducted in four rainfed-prone sites in Nueva Ecija, Negros Occidental, North Cotabato, and Ilocos Norte during the wet seasons of 2015 and 2016. Across sites, RILs recorded an average yield of 2.631 t/ha; four of them had higher yields than their parentals by 4 – 10%.
Under submergence, 5 inbred lines were reported to be “tolerant to highly tolerant” during seedling stage while 3 inbred lines were found to be “moderately tolerant” at vegetative stage. For drought, all lines were found to be “moderately tolerant to tolerant” in both seedling and reproductive stages.
One breeding line, PR39954-B-15-2-4-1-1, was identified as most stable in terms of yield and adaptability across test sites. Grain yield averaged 2.710 t/ha across sites, with maximum yield potential of 4.857 t/ha and yield advantage of 9% over PSB Rc14 and PSB Rc68.
“The lines are undergoing pest and disease resistance assessments as well as grain quality evaluation,” said Conception.
The researchers also found that the RILs flowered and matured earlier than PSB Rc68.
