scholarly journals Intra-Plant Variability for Heat Tolerance Related Attributes in Upland Cotton

Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2375
Author(s):  
Aneeq ur Rehman ◽  
Iqrar Ahmad Rana ◽  
Sajid Majeed ◽  
Muhammad Tanees Chaudhary ◽  
Mujahid Zulfiqar ◽  
...  

Abiotic stress, particularly heat stress, affects various parts of the cotton plant and ultimately impacts the seed cotton yield. Different portions of a single cotton plant of a cultivar exhibit variable responses to stress during reproductive and vegetative phases. To test this hypothesis, physiological and morphological traits related to heat stress were observed for two flowering positions in 13 genotypes of upland cotton. These genotypes were sown in field conditions in triplicate following a randomized complete block design. Data were collected for pollen germination, pollen viability, cell membrane thermostability, chlorophyll content, boll weight, and boll retention for both the top and bottom branches of each genotype. The collected data were analyzed for the identification of variability within and between genotypes for these two flowering positions. Tukey’s test was applied to estimate the significance of differences between genotypes and positions within each genotype. Results showed that the two positions within the same plant statistically varied from each other. The bottom branches of the genotypes performed significantly better for all traits measured except boll weight. The genotype AA-933 performed best for pollen germination and boll retention, while CYTO-608 exhibited maximum pollen viability in both the bottom and top flower positions compared with other genotypes. Overall, MNH-1016 and CIM-602 showed better cell membrane thermostability and chlorophyll content, respectively. This intra-plant variability can be further exploited in breeding programs to enhance the stress tolerance capabilities of the resulting varieties.

2019 ◽  
Vol 157 (04) ◽  
pp. 283-299 ◽  
Author(s):  
C. Malumpong ◽  
S. Cheabu ◽  
C. Mongkolsiriwatana ◽  
W. Detpittayanan ◽  
A. Vanavichit

AbstractThe reproductive stage of rice is the most sensitive to heat stress, which can lead to spikelet sterility. Thus, heat-tolerant and heat-susceptible genotypes were used to investigate their differences in terms of phenotypic responses and expression changes of Hsf genes at the pre-flowering stage under heat stress. Results clearly showed that panicles had the highest temperature compared with other plant parts under both natural and heated conditions. However, the temperatures of tolerant and susceptible genotypes were not significantly different. In terms of spikelet fertility, the tolerant lines M9962 and M7988 had high seed set because their anther dehiscence, pollen viability and pollen germination were only slightly affected. In contrast, the susceptible line Sinlek showed severe effects at all steps of fertilization, and the pollen viability of M7766 was slightly affected under heat stress but was more affected in terms of anther dehiscence and pollen germination. Both susceptible lines showed dramatically decreased seed set. In addition, the expression of six HsfA genes in the flag leaves and spikelets at the R2 stage of plants under heat stress showed different responses. Notably, expression of the HsfA2a gene was predominantly upregulated in the flag leaf and spikelets under heat stress in M9962. Therefore, it can be concluded that heat stress has severe effects on the stamen, and that different genotypes have different susceptibilities to heat stress.


2012 ◽  
Vol 39 (12) ◽  
pp. 1009 ◽  
Author(s):  
Viola Devasirvatham ◽  
Pooran M. Gaur ◽  
Nalini Mallikarjuna ◽  
Raju N. Tokachichu ◽  
Richard M. Trethowan ◽  
...  

High temperature during the reproductive stage in chickpea (Cicer arietinum L.) is a major cause of yield loss. The objective of this research was to determine whether that variation can be explained by differences in anther and pollen development under heat stress: the effect of high temperature during the pre- and post-anthesis periods on pollen viability, pollen germination in a medium, pollen germination on the stigma, pollen tube growth and pod set in a heat-tolerant (ICCV 92944) and a heat-sensitive (ICC 5912) genotype was studied. The plants were evaluated under heat stress and non-heat stress conditions in controlled environments. High temperature stress (29/16°C to 40/25°C) was gradually applied at flowering to study pollen viability and stigma receptivity including flower production, pod set and seed number. This was compared with a non-stress treatment (27/16°C). The high temperatures reduced pod set by reducing pollen viability and pollen production per flower. The ICCV 92944 pollen was viable at 35/20°C (41% fertile) and at 40/25°C (13% fertile), whereas ICC 5912 pollen was completely sterile at 35/20°C with no in vitro germination and no germination on the stigma. However, the stigma of ICC 5912 remained receptive at 35/20°C and non-stressed pollen (27/16°C) germinated on it during reciprocal crossing. These data indicate that pollen grains were more sensitive to high temperature than the stigma in chickpea. High temperature also reduced pollen production per flower, % pollen germination, pod set and seed number.


2016 ◽  
Vol 67 (7) ◽  
pp. 712 ◽  
Author(s):  
Shoaib Ur Rehman ◽  
Muhammad Bilal ◽  
Rashid Mehmood Rana ◽  
Muhammad Naveed Tahir ◽  
Muhammad Kausar Nawaz Shah ◽  
...  

Heat and drought are among the major obstacles confronting crop production under climate change. The present study was conducted to evaluate 50 diverse wheat genotypes for cell membrane stability (CMS) and chlorophyll content at seedling and anthesis stages under heat and drought stress conditions, to understand the effect of the two abiotic factors and to find promising genotypes for future breeding. Experiments were conducted in the glasshouse (seedling stage) and the field (anthesis stage). Analysis of variance showed significant variation (P ≤ 0.05) for all of the traits at seedling and anthesis stages. High levels of broad-sense heritability and genetic advance at 5% selection intensity indicated the presence of a high genetic component of variation and potential for genetic improvement through selection among the existing genetic variation. CMS showed a significant positive correlation with 1000-grain weight (TGW) under heat and drought conditions at both seedling and anthesis stages. Chlorophyll a/b ratio at seedling stage exhibited a significant negative correlation (r = –0.39, P < 0.05) with TGW under heat stress. Total chlorophyll content was significantly (r = 0.42, P < 0.05) correlated with TGW under heat stress at anthesis. Genotypes ETAD248 and ETAD7 showed the highest CMS and TGW values, whereas their chlorophyll a/b values were lowest, at both seedling and anthesis stages under heat and drought stress conditions. Higher CMS and total chlorophyll content, and lower chlorophyll a/b, were found to be useful indicators to identify genotypes with high TGW under heat and drought stress conditions. This study indicated the possibility of using seedling resistance as an indicator for later stage response in breeding for heat and drought resistance. The resistant genotypes identified can be used as potential germplasm in breeding programs.


2020 ◽  
Vol 12 (8) ◽  
pp. 135
Author(s):  
Sergio Castro-Nava ◽  
Rafael Delgado-Martínez ◽  
Jose Manuel García-Girón

Heat stress is the major abiotic stressor in agriculture which reduces crop productivity and yield. Six sugarcane (Sacharum officinarum L.) genotypes were studied to investigate the impact of three temperature levels at four phenological stages on tissue electrolyte production and the feasibility of using the cell thermostability method (CTM) for the identification and selection of heat tolerant sugarcane genotypes. The cell membrane thermostability was quantified by measuring relative cell injury percentage with a modification in the temperature treatment on four phenological stages in a field experiment. Our results suggest that heat tolerance based on cell membrane thermostability can be improved using the existing genetic variability available within the commercial or experimental sugarcane germplasm. We conclude that the cell membrane thermostability test can be a useful screening procedure for selecting sugarcane genotypes that tolerate high temperature stress. The test can be used in conjunction with a temperature trait of 60 &deg;C during the maturity stage. This procedure predicts the ability of sugarcane genotypes to maintain yield and juice quality under stressful field conditions.


HortScience ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 216-226 ◽  
Author(s):  
Neil O. Anderson ◽  
Mi-kyoung Won ◽  
Dong-chan Kim

Global warming has created increased nighttime temperatures both in field and greenhouse production of chrysanthemums during flower bud initiation (FBI) and development, causing heat delay or complete cessation of flowering. Integration of breeding and selection for heat delay insensitivity (HDI) has become imperative for greenhouse (cut, potted types) and must be accomplished on a genotypic basis, similar to winterhardiness. This is a breeding objective in the joint garden chrysanthemum breeding project between the Chungnam Provincial Agricultural Research and Extension Services and the University of Minnesota. The objectives of this research were to test 10 genotypes (cultivars, seedlings) from both breeding programs when grown in low-temperature (LT) and high-temperature (HT) short-day (SD) and long-day (LD) conditions (four environments: LTSD, LTLD, HTSD, and HTLD); determine the extent of heat delay and HDI for visible bud date (VBD), flowering, and other phenotypic traits; evaluate relative injury (RI) and cell membrane thermostability (CMT), and to select future parents with lowered RI values, higher CMT, shorter heat-induced flowering delay, and/or HDI. ‘Magic Ball’ and ‘Minnwhite’ had the shortest plant height in HTLD and HTSD, whereas ‘Geumbangul’ had stability for height in all treatments. Lowest long day leaf numbers (LDLN) occurred under LTSD in seven genotypes. However, both ‘Geumbangul’ and ‘Magic Ball’ had complete stability for LDLN across all environments. Sigmoid curves for RI% and temperature were found for all genotypes and environments with R2 = 0.79–0.89. Only ‘Mellow Moon’ had stability or equal VBDs in HTSD, LTSD, and LTLD conditions. This is the first-ever report of stability for VBD across inductive and noninductive HT/LT treatments. Only ‘Centerpiece’ flowered in all environments and also had 0 day of heat for VBD in LT and 1 day of heat delay in HT, as well as three others (Mn. Sel’n. 01-210-43, ‘Autumn Fire’, and ‘Geumbangul’). Few had linear regressions with positive slopes for heat-induced VBD or flowering delay regressed with RI%; most had no slope (R2 ≈ 0.0) for all treatments (‘Centerpiece’, Mn. Sel’n. 01-210-43), whereas others were negative (‘Mammoth™ Dark Bronze Daisy’, Flw LTLD–LTSD). Surprisingly, one linear regression had a slope of R2 = 1.0 (‘Geumbangul’, Flw LTLD–LTSD). These responses are all novel in chrysanthemums. Selecting the best parents in both breeding programs to maximize stability of all traits across these four environments with minimal crossing and selection across generations could be accomplished by stacking parental traits. A crossing scheme involving just three parents is proposed to incorporate stability for all traits in just a few generations.


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