Root traits and cellular level tolerance hold the key in maintaining higher spikelet fertility of rice under water limited conditions

Abstract

Reduced spikelet fertility appears to be one of the major factors responsible for the decreased rice grain yield when cultivated under semi irrigated aerobic condition. We demonstrate that genotypes with better root systems coupled with higher cellular level tolerance (CLT) can significantly improve spikelet fertility under semi-irrigated aerobic condition in the field. A set of 20 contrasting rice accessions differing in root traits and CLT with significant molecular diversity were subjected to specific soil moisture regimes during a period between five days before and 10 days after anthesis. Lowest spikelet fertility was observed among the plants grown under water limited (WL) conditions followed by the plants grown aerobically in field conditions (AF). Deep rooted genotypes generally maintained higher spikelet fertility under both WL and AF conditions. Furthermore, genotypes that had high roots biomass as well as high CLT recorded the lowest reduction in spikelet fertility under WL and AF compared with the low root and low CLT genotype. This study emphasised the relevance of combining water acquisition and CLT for improving field level tolerance of rice to water limitation. Such genotypes recorded significantly higher grain yield under stress as well as well watered conditions. The study led to the identification of promising trait donor genotypes which can be exploited in breeding to develop superior trait pyramided cultivars suitable for semi irrigated aerobic cultivation.

Acquired Thermo‐Tolerance and Trans‐Generational Heat Stress Response at Flowering in Rice

“…, Raju et al. ). However, most studies mentioned above have documented thermo‐tolerance in seedlings (Kumar et al.…”

“…, Senthil‐Kumar and Udayakumar , Raju et al. ) or at the whole‐plant level during the vegetative stage (Wollenweber et al. , Wang et al.…”

“…The ability of a plant to survive lethal heat stress by virtue of a prior exposure to mild non-damaging stress is defined as acquired thermo-tolerance (Sung et al 2003). Many plant species show improved tolerance via survival and post-stress recovery growth accompanied by higher production of chaperons/HSPs in acclimated (pre-treatment) compared with non-acclimated (without pre-treatment) conditions (Key et al 1981, Hong et al 2003, Wahid et al 2007, including rice (Lin et al 2014, Raju et al 2014. However, most studies mentioned above have documented thermo-tolerance in seedlings (Kumar et al 1999, Srikanthbabu et al 2002, Senthil-Kumar and Udayakumar 2004, Raju et al 2014 or at the whole-plant level during the vegetative stage (Wollenweber et al 2003).…”

Does Morphological and Anatomical Plasticity during the Vegetative Stage Make Wheat More Tolerant of Water Deficit Stress Than Rice?

“…Pots with the control treatment were maintained at 100% field capacity throughout the experiment, while water deficit stress was imposed by unplugging the stoppers at the bottom of the pots. A standardized gravimetric approach of daily pot weighing (Raju et al, 2014) was followed to gradually attain 55% to 60% field capacity and thereafter maintained at the same level until the end of the experiment (for details, see Supplemental Fig. S3).…”

Emerging tools, concepts and ideas to track the modulator genes underlying plant drought adaptive traits: An overview

“…[12][13] There are also recent evidences emphasizing the importance of combining water acquisition and CT traits for maintaining higher spikelet fertility in rice under drought stress thereby enhancing field level tolerance to water limitation. 14 In addition to water extraction from drying soil, water conservation strategies to retain tissue water are crucial for drought adaptation. Water conservation depends upon stomatal and non-stomatal transpiration, among which the later seems to be the crucial component since cuticular transpiration can happen continuously during day and night under dry conditions where vapour pressure deficit (VPD) will be high.…”