The apparent climatic extremes affect the growth and developmental process of cool-season grain legumes, especially the high-temperature stress. The present study aimed to investigate the impacts of high-temperature stress on crop phenology, seed set, and seed quality parameters, which are still uncertain in tropical environments. Therefore, a panel of 150 field pea genotypes, grouped as early (n = 88) and late (n = 62) maturing, were exposed to high-temperature environments following staggered sowing [normal sowing time or non-heat stress environment (NHSE); moderately late sowing (15 days after normal sowing) or heat stress environment-I (HSE-I); and very-late sowing (30 days after normal sowing) or HSE-II]. The average maximum temperature during flowering was about 22.5 ± 0.17°C for NHSE and increased to 25.9 ± 0.11°C and 30.6 ± 0.19°C in HSE-I and HSE-II, respectively. The average maximum temperature during the reproductive period (RP) (flowering to maturity) was in the order HSE-II (33.3 ± 0.03°C) > HSE-I (30.5 ± 0.10°C) > NHSE (27.3 ± 0.10°C). The high-temperature stress reduced the seed yield (24–60%) and seed germination (4–8%) with a prominent effect on long-duration genotypes. The maximum reduction in seed germination (>15%) was observed in HSE-II for genotypes with >115 days maturity duration, which was primarily attributed to higher ambient maximum temperature during the RP. Under HSEs, the reduction in the RP in early- and late-maturing genotypes was 13–23 and 18–33%, suggesting forced maturity for long-duration genotypes under late-sown conditions. The cumulative growing degree days at different crop stages had significant associations (p < 0.001) with seed germination in both early- and late-maturing genotypes; and the results further demonstrate that an extended vegetative period could enhance the 100-seed weight and seed germination. Reduction in seed set (7–14%) and 100-seed weight (6–16%) was observed under HSEs, particularly in HSE-II. The positive associations of 100-seed weight were observed with seed germination and germination rate in the late-maturing genotypes, whereas in early-maturing genotypes, a negative association was observed for 100-seed weight and germination rate. The GGE biplot analysis identified IPFD 11-5, Pant P-72, P-1544-1, and HUDP 11 as superior genotypes, as they possess an ability to produce more viable seeds under heat stress conditions. Such genotypes will be useful in developing field pea varieties for quality seed production under the high-temperature environments.

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Mungbean seeds, despite being protected inside the pod, are susceptible to pre-harvest sprouting (PHS) following rainfall due to lack of fresh seed dormancy (FSD), which deteriorates the quality of the seed/grain produced. Therefore, development of mungbean cultivars with short (10–15 days) period of FSD has become important to curtail losses incurred by PHS. In this study, we investigated variations in PHS, fresh seed germination (FSG) and activity of α-amylase enzyme in diverse mungbean genotypes. There was a wide variation in PHS tolerance and FSG among 163 genotypes examined and 14 genotypes were found to be tolerant (<20%) to PHS. Seed germination in a pod, a measure used to evaluate PHS, varied from 7.14% in germplasm accession Chamu 4 to 82.52% in cultivated variety IPM 2–3. There was a marked increase in α-amylase activity in genotypes showing high FSG and PHS, especially at 48 and 72 h after germination as compared with PHS tolerant genotypes. Therefore, α-amylase can be used as an effective biochemical marker to evaluate a large number of mungbean genotypes for FSD and PHS. Also, the variation in seed germinability as found in this study could be further used for mungbean improvement programme.

Aim: Methodology:Results: Interpretation:Pigmented (desi) and non pigmented (kabuli) cultivars of chickpea are known to differ in seed vigour. Therefore, the main objective of the study was to understand the mechanisms for such vigour differences and to identify the important seed coat and seed related vigour traits that makes the coloured desi seeds more vigorous then unpigmented kabuli seeds.Twenty two chickpea genotypes differing in seed coat colour were included in the experiment. Field emergence and electrical conductivity of seed leachate was used as vigour indicator. Hundred-seed weight, proportion of seed coat, laboratory germination, electrical conductivity, water imbibition pattern, tannin, lignin and total phenol content, presence or absence of air space between seed coat and cotyledon and status of hilum-micropylar region were studied to understand the mechanism for vigour differences between pigmented desi and unpigmented kabuli genotypes.Despite a high laboratory germination (>89%) of all cultivars, unpigmented kabuli genotypes recorded low (39-69%) FE then pigmented desi genotypes (64-87%). Rapid rate of water imbibition (111.86-145.09%), lower proportion of seed coat (4.76-6.78%), greater electrical conductivity of seed leachate (49-172 -1 µS cm g ), low content of lignin (0.74-2.41), tannin (0.18-1.09 µg mg ) and total phenol (1.66-5.58 µg mg ) was associated with low field emergence in unpigmented kabuli types. Besides, air space between seed coat and cotyledon, open hilum-micropylar region, less polyphenolic content and low proportion of seed coat potentially describe the rapid water uptake by unpigmented kabuli genotypes making them vulnerable to imbibitional damage.Rather than laboratory germination, electrical conductivity may be used as an indicator for determining field emergence in chickpea. Screening/ developing unpigmented kabuli genotypes with seeds having lower rate of water imbibition could be a promising way to enable seed vigour improvement in chickpea.