Incorporating Drought and Submergence Tolerance QTL in Rice (Oryza sativa L.)—The Effects under Reproductive Stage Drought and Vegetative Stage Submergence Stresses

Abstract

Drought and submergence have been the major constraint in rice production. The present study was conducted to develop high-yielding rice lines with tolerance to drought and submergence by introgressing Sub1 into a rice line with drought yield QTL (qDTY; QTL = quantitative trait loci) viz. qDTY3.1 and qDTY12.1 using marker-assisted breeding. We report here the effect of different combinations of Sub1 and qDTY on morpho-physiological, agronomical traits and yield under reproductive stage drought stress (RS) and non-stress (NS) conditions. Lines with outstanding performance in RS and NS trials were also evaluated in vegetative stage submergence stress (VS) trial to assess the tolerance level. The QTL class analysis revealed Sub1 + qDTY3.1 as the best QTL combination affecting the measured traits in RS trial followed by Sub1 + qDTY12.1. The effects of single Sub1, qDTY3.1 and qDTY12.1 were not as superior as when the QTLs are combined, suggesting the positive interaction of Sub1 and qDTY. Best performing lines selected from the RS and NS trials recorded yield advantage up to 4453.69 kg ha−1 and 6954 kg ha−1 over the parents, respectively. The lines were also found having great tolerance to submergence ranging from 80% to 100%, contributed by a lower percentage of shoot elongation and reduction of chlorophyll content after 14 days of VS. These lines could provide yield sustainability to farmers in regions impacted with drought and submergence while serving as important genetic materials for future breeding programs.

Identification of Drought Tolerant Rice (Oryza Sativa L.) Genotypes with Asian and African Backgrounds

“…This implies the possibility of selecting most drought-tolerant lines for their further use by farmers or by the breeding program. Comparable results were reported by Mohd Ikmal et al [ 23 ] in BC1 F4 lines. Spikelet fertility and yield components were significantly reduced by drought stress.…”

Rice Responses to Water Limiting Conditions: Improving Stress Management by Exploiting Genetics and Physiological Processes

“…A MABC approach was used to obtain drought and submergence-tolerant indica rice lines in the background of the elite variety UKM5, which harbor the drought yield QTLs (qDTY3.1 and qDTY12.1), using IR64-Sub1 as the donor of the submergence tolerance locus Sub1. The best-performing combination was that with Sub1 and qDTY3.1, which was characterized by higher grain yield under drought in the reproductive stage, demonstrating a positive effect of the Sub1 locus on drought tolerance when it was combined with the drought yield QTLs [103]. A similar approach was adopted to increase water-stress tolerance in Improved White Ponni (IWB), a rice variety popular in South India, which is characterized by high yield, fine grain, and high cooking quality, but it is susceptible to drought, salinity, and submergence [104].…”

Integration of miRNA dynamics and drought tolerant QTLs in rice reveals the role of miR2919 in drought stress response

“…Drought tolerant NI (near isogenic) lines, introgressed with two drought tolerant QTLs ( qDTY2.1 and qDTY3.1) , specific to reproductive stage, were developed in the high yielding elite cultivar, Pusa 44, through marker assisted backcross breeding [ 17 ]. In South East Asia, many abiotic stress tolerant varieties have been released for commercial cultivation, following marker-assisted pyramiding of QTLs for drought/salinity/submergence tolerance [ 18 , 19 ]. Several QTLs have been identified for drought tolerance at vegetative stage and reproductive stage for different drought component traits including a few yield under drought QTLs.…”