Effect of drought stress on phenological and yield attributes in Wheat (Triticum aestivum L.)

Abstract

Investigations on drought stress treatment in terms of phenological and yield attributes carried out with wheat varieties (WH 1105 and WH 1025) under field conditions revealed that the number of days to heading, under drought stress conditions decreased by 5 days.  The number of days to anthesis were also found less in drought conditions. It was 100 and 103 days in WH 1105 and WH 1025, respectively. The grain filling period was shortened in WH 1025. The drought-stressed varieties reached to maturity 5 days earlier compared to irrigated ones.  The yield attributes such as grain number per spike, grain weight per spike (g), test weight (g), and grain yield per square meter (g/m 2) under drought also decreased to a great extent. The Drought Susceptibility Index (DSI) calculated for two wheat varieties was 1.25 and 0.71 in WH 1105 and WH 1025, respectively. The results showed that the wheat variety WH 1025 registered better drought tolerance than WH 1105. Agriculture is facing the greatest challenge to meet the food requirements of the ever-growing population in the world. There is intense pressure on the scientific community to further enhance the productivity of major cereal crops.  Wheat is one of the major food crops that feed nearly half of the world’s population (Dhakal 2021). According to the predicted trends, wheat production will be affected due to climate change (Aaron et al., 2020). Scenarios of changing climate suggest that water-deficient conditions at the grain filling stage could reduce crop yields in arid and semi-arid regions in most parts of the world (Hafiz et al., 2020). Wheat growing areas in India are frequently hit by moderate to severe droughts particularly when the crop is at the stage of anthesis. Less availability of water during drought periods forces plants to use limited moisture as efficiently as possible. High-temperature during extreme in of weather conditions associated with drought further aggravate the risk of drought (IPCC 2007). Significant changes are expected to occur with regard to wheat phenological parameters (Jessica et al., 2020). The negative changes that occur in phenological traits considerably reduce the time of maturity of the crop and ultimately affecting the yield attributes (Hester and Alison 2021). Wheat plants, stressed for water at different stages of growth, mature earlier than the plants under normal conditions (Nisar et al. 2007). Drought adversely affects the crop developmental stages and shorten the grain filling period by decreasing potential yields (Brooks et al. 1982). Shortening of days to heading, days to maturity, and grain filling period under high-temperature stress in wheat have been reported (Mahboob et al. 2005). The variability of climate and the frequent onset of droughts are responsible to cause a change in yield attributes such as number of spikes per square meter, test weight, the weight of grains per spike and biological yield were the most effective variables influencing grain yield and suggesting that high yield of wheat plants under drought conditions could be obtained by selecting suitable breeding materials (Leilah & Al-Khateeb, 2005). Previous investigators have also studied the impacts of drought stress on phenological parameters in highly controlled environments or pot culture experiments with no adequate data of crop performance under field conditions. Empirical studies on wheat in open airfields are scarce. Hence, the present study about the impacts of drought stress on various phenological parameters and yield attributes under field conditions in (varieties WH 1105 and WH 1025) was carried out. The aim of this experiment was to determine how drought stress treatment at the grain filling stage, influence phenological parameters and yield attributes.