EFFECT OF TEMPERATURE AND PHOTOTHERMAL QUOTIENT ON THE YIELD COMPONENTS OF WHEAT (Triticum aestivum L.) IN INDO-GANGETIC PLAINS OF INDIA

Abstract

To quantify the effect of thermal stress and photothermal quotient (PTQ) on yield components, eleven years experimental data of three cultivars (HD-2285, K-8804 and K-9107) under three sowing dates at Kanpur centre were analysed. Number of grains per ear (NG), grain weight per ear (GW) and 1000-grain weight (TG) were identified as prime yield contributing components in HD-2285, K-8804 and K-9107, respectively. GW was highly sensitive to maximum temperature (MXT) while NG was sensitive to minimum temperature (MNT) during jointing (JNT) to anthesis (ATS) as well as the total growing season in all the cultivars. In both HD-2285 and K-8804, optimum MXT and MNT during JNT to ATS are 22.7-24.6 and 7.0-7.9°C, respectively for obtaining maximum NG. Optimum MXT for GW ranged from 15.8-17.3°C during tillering (TLR) to JNT stage in K-8804 and K-9107 while it was 20.4°C during JNT to ATS stage in HD-2285. MXT, MNT and PTQ of 23.6°C, 9.2°C and 25 MJ/m 2 /day/°C, respectively during JNT to ATS in K-9107 were found optimum for higher TG.

Effect of tillers on corn yield: Exploring trait plasticity potential in unpredictable environments

“…Soil properties are key to yield potential in the evaluated region (Lobell & Azzari, 2017), and plant nutrition is key to tiller appearance and survival as demonstrated by Sangoi et al (2011). The PTQ relationship in corn tillers is novel, and consistent with reports on the link to tiller appearance, tiller number, and productivity in other grasses such as wheat (Triticum aestivum L.) and grain sorghum (Sorghum bicolor L. Moench) (Fischer, 1985;Kim et al, 2010;Kumar et al, 2016). A greater PTQ results in a larger potential photosynthate source for the plant at a given timepoint (Nix, 1976).…”

Statistical Modeling of Phenotypic Plasticity under Abiotic Stress in Triticum durum L. and Triticum aestivum L. Genotypes

“…A steady increase in population density has been a driver of maize- [74], sorghum- [68], but not wheat-yield improvements, where higher-yielding environments have maximum yields at higher population density. Despite the negative relationship between population density and fertile tillers [32,69], their plasticity estimates covaried positively ( Figure 3); thus, confirming that a trait and its plasticity can be independent, and PP is under its own genetic control under a specific abiotic stress [28].…”

“…Plasticity may be constrained by its high (energy) cost, developmental factors, or unpredictable environmental cues regulating plant development [69]. Therefore, the decreasing plasticity of wheat in the order: fertile tillers > kernels m −2 > kernel weight can be attributed to differential costs and contributions to yield components, stabilizing selection for kernel weight, and directional changes in resource (i.e., light, water, and nutrients) availability during plant ontogeny [25,27].…”

“…Growth stages differed markedly (71.4%) in their PPs (Table 2) and at the discrimination level between and within wheat genotypes (Figure 2). Larger level of discrimination at FM than RP could be attributed to differences in the sequentially developed yield components, such as tiller [20,69]. The implications of differential plastic responses to the same abiotic stress as a function of growth stage (Figure 2) are of practical significance [31,48].…”

Meteorological conditions and their associations with the productive performance of wheat

“…Here, PQ is the daily photothermal quotient (MJ m -2 day °C), RS is the global solar radiation (MJ m -2 day), Tmed is the mean daily temperature (°C) and Tb is the basal temperature. This quotient photothermal can be used to predict or explain wheat production (Kumar et al, 2016) and frost risk to identify suitable sowing dates for wheat (Silva et al, 2014), estimation of wheat grain yield (Ratjen et al, 2012). The PQ can be used to identify sowing times and regions that maximize grain yield potential (Nalley et al, 2009;Silva et al, 2014).…”