Effect of morpho-physiological traits on grain yield of sorghum grown under stress at different growth stages, and stability analysis

Abstract

SUMMARYRecent trends in climate change resulting in global warming and extreme dry spells during rainy seasons are having a negative impact on grain and fodder production in rain-fed crops in India. Understanding the mechanisms of drought tolerance at various growth stages will help in developing tolerant genotypes. Crosses were made between elite and drought-tolerant sorghums, and F2and F3progenies were evaluated for drought tolerance in multiple locations. Twenty-five F4/F5derivatives along with drought-tolerant check plants (two high-yielding genotypes showing moderate drought tolerance: C43 (male parent of the commercial hybrid CSH 16, tolerant to drought) and CSV 17, (a pure line commercial cultivar released for drought-prone areas) were screened for drought tolerance under a factorial randomized block design with three replications during the rain-free months of April–June in 2007 and 2008 at Tamil Nadu Agricultural University, Kovilpatti, India. In each generation/year, four trials were conducted and water stress at different phases of crop growth,viz. vegetative, flowering and post-flowering (maturity), was imposed by withholding irrigation. Observations were recorded on grain and straw yields, plant height, number of roots, root length, leaf relative water content (LRWC), chlorophyll content and stomatal conductance under all treatments. The traits, grain yield, plant height, average root length and stomatal conductance showed significant mean sums of squares (SSs) for genotype × environment (G × E), suggesting that genotypes had significant differential response to the changing environments. Significant mean SSs due to G × E (linear) were obtained for straw yield, LRWC and chlorophyll content, indicating that the variability is partly genetic and partly influenced by environment. Grain yield was correlated with chlorophyll content (r = 0·43) at the vegetative stage, with number of roots (r = 0·49), LRWC (r = 0·51), chlorophyll content (r = 0·46) and stomatal conductance (r = −0·51) at the pre-flowering stage, and with LRWC (r = 0·50) and stomatal conductance (r = −0·40) at the post-flowering stage, under water stress. Partial least square (PLS) analysis showed that different traits were important for grain yield under water stress at different growth stages. Pyramiding the genes for the traits responsible for high grain yield under stress will help in developing stable genotypes at different stages of plant growth.

Yield enhancement by short‐term imposition of severe water deficit in the vegetative growth stage of grain sorghum

“…In reviewing the literature on this topic in sorghum, we concluded that the studies from which substantial yield reductions were reported were characterised by imposition of water deficit for relatively long periods, usually 15 days or greater, often including lengthy dry‐down periods for stress development and often with stress extending into the reproductive stage (e.g. Inuyama et al., ; Lewis et al., ; Sankarapandian et al., ). Studies that reported yield maintenance seem to be characterised by mild water deficit stress, with varied duration and with some cultivar response differences observed (Craufurd & Peacock, ; Munamava & Riddoch, ).…”

“…Water deficit can negatively affect the yield of crops, including grain sorghum (Assefa, Staggenborg, & Prasad, ; Lesk, Rowhani, & Ramankutty, ). But the effects of water deficit on crop yield often have a strong interaction with the timing of the stress relative to the stage of growth of the plant and the severity of stress (Abid et al., ; Rowland et al., ; Sankarapandian et al., ). Researchers have long studied the details of this phenomenon in order to prescribe strategies to avoid or minimise yield loss (Cui et al., ; Eck & Musick, ; Munamava & Riddoch, ; Rowland et al., ).…”

“…In reviewing these reports, it seems that the studies from which substantial yield reductions were reported are characterised by imposition of water deficit for periods of 15 days or greater, often including lengthy dry‐down periods for stress development, and often extending into the reproductive stage (e.g. Inuyama et al., ; Lewis et al., ; Sankarapandian et al., ). Several reports show maintenance of yield in a numbers of crops, including sorghum, when water deficit was applied during vegetative growth, and enhancement of yield has been reported in cotton and wheat.…”

Agronomic Evaluation of Sorghum Hybrids for Silage Production Cultivated in Semiarid Conditions

“…In arid and semiarid regions, sorghum is an important source of roughage because of its morpho-physiological adaptations to the water stress that provide high dry matter yield (DMY) and adaptability in areas with uneven distribution of rainfall (Sankarapandian et al, 2013; Ahmeda et al, 2016; Rakshit et al, 2016; Su-jiang et al, 2016). …”

“…Sorghum is an important forage crop used in livestock systems in many regions around the world because of its adaptation to different environments (Sanchez et al, 2002 ; Fonseca et al, 2012 ; Amelework et al, 2015 ). In arid and semiarid regions, sorghum is an important source of roughage because of its morpho-physiological adaptations to the water stress that provide high dry matter yield (DMY) and adaptability in areas with uneven distribution of rainfall (Sankarapandian et al, 2013 ; Ahmeda et al, 2016 ; Rakshit et al, 2016 ; Su-jiang et al, 2016 ).…”