Abstract
Drought has been a major limiting factor for rice production. Drought yield QTLs (qDTYs; QTLs = quantitative trait loci) were pyramided into MRQ74 and MR219 to produce drought tolerant lines. In this study, new drought tolerant MRQ74 and MR219 pyramided lines (PLs) were evaluated under drought stress (RS) and non-stress (NS) conditions to evaluate the effects of different qDTYs combinations on morphological and agronomical traits. MRQ74 PLs having qDTY12.1 possessed the best root length (RL) under both RS and NS but the effect was only significant for MR219 PLs under RS. Some qDTYs combinations also found to have consistent effect on the same trait of both populations. PLs with only qDTY12.1 showed the highest grain yield (GY) under RS in both populations which means qDTY12.1 controlled RL and caused higher GY under drought condition. The interaction of major-effect qDTY12.1 with qDTY2.2 also shows significant effect on leaf rolling (LR) of both PL populations. These qDTYs proved to be beneficial in improving traits related to drought tolerance. Selected PLs with qDTY12.1 combinations also found to have better RL and root weight (RW) under RS. Improvement of morphological and agronomical traits led to higher GY of PLs. Therefore, qDTY12.1 either is present singly or in combination with other qDTYs was the best qDTY due to its consistent effect on morphological and agronomical traits and GY across populations under RS and NS.
Highlights
Rice, which was produced 600 million tons on an area of more than 150 million hectares, has become the main source of daily calories for more than 3.5 billion people in Asia, Africa and LatinAmerica [1,2]
This study focused on evaluating the drought tolerant pyramided lines (PLs) of MRQ74 and MR219 under RS and NS with the objectives to identify morphological and agronomical traits which respond to RS, to identify morphological and agronomical traits which are related to different combinations of qDTYs and to identify qDTY/s with the most effective and consistent effects on both PL populations under NS and RS
We found that the effect of every qDTY classes to any traits of both PL populations seem to Droughtamong imposition in thisand study was considered mild or moderate level of with waterqDTY/s depth be different population between
Summary
Rice, which was produced 600 million tons on an area of more than 150 million hectares (ha), has become the main source of daily calories for more than 3.5 billion people in Asia, Africa and LatinAmerica [1,2]. Rice, which was produced 600 million tons on an area of more than 150 million hectares (ha), has become the main source of daily calories for more than 3.5 billion people in Asia, Africa and Latin. In Malaysia, each Malaysian consumed 78.8 kg rice per year on average. For the past few years, Malaysia’s rice self-sufficiency level (SSL) was at 71% and average yield was around 3.0 to. To add the shortage of 29% SSL, rice were imported from countries such as Thailand, Vietnam, Pakistan and India. Malaysia population size is increasing year by year and the latest figure in 2016 was 31.7 million. Production of rice in local rice fields needs to be increased to feed the population. Drought, which is perilous to rice can thwart the effort to increase rice production and would drive bad consequences to national food security
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