scholarly journals Abnormal anther development leads to lower spikelet fertility in rice (Oryza sativa L.) under high temperature during the panicle initiation stage

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qiuqian Hu ◽  
Wencheng Wang ◽  
Qifan Lu ◽  
Jianliang Huang ◽  
Shaobing Peng ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
High Temperature ◽  
Grain Yield ◽  
Heat Tolerance ◽  
Pollen Viability ◽  
Anther Development ◽  
Spikelet Fertility ◽  
Anther Wall ◽  
Anther Dehiscence ◽  
Initiation Stage

Abstract Background Decreased spikelet fertility is often responsible for reduction in grain yield in rice (Oryza sativa L.). In this study, two varieties with different levels of heat tolerance, Liangyoupeijiu (LYPJ, heat susceptible) and Shanyou63 (SY63, heat tolerant) were subjected to two temperature treatments for 28 days during the panicle initiation stage in temperature/relative humidity-controlled greenhouses: high temperature (HT; 37/27 °C; day/night) and control temperature (CK; 31/27 °C; day/night) to investigate changes in anther development under HT during panicle initiation and their relationship with spikelet fertility. Results HT significantly decreased the grain yield of LYPJ by decreasing the number of spikelets per panicle and seed setting percentage. In addition, HT produced minor adverse effects in SY63. The decreased spikelet fertility was primarily attributed to decreased pollen viability and anther dehiscence, as well as poor pollen shedding of the anthers of LYPJ under HT. HT resulted in abnormal anther development (fewer vacuolated microspores, un-degraded tapetum, unevenly distributed Ubisch bodies) and malformation of pollen (obscure outline of the pollen exine with a collapsed bacula, disordered tectum, and no nexine of the pollen walls, uneven sporopollenin deposition on the surface of pollen grains) in LYPJ, which may have lowered pollen viability. Additionally, HT produced a compact knitted anther cuticle structure of the epidermis, an un-degraded septum, a thickened anther wall, unevenly distributed Ubisch bodies, and inhibition of the confluent locule, and these malformed structures may be partially responsible for the decreased anther dehiscence rate and reduced pollen shedding of the anthers in LYPJ. In contrast, the anther wall and pollen development of SY63 were not substantially changed under HT. Conclusions Our results suggest that disturbed anther walls and pollen development are responsible for the reduced spikelet fertility and grain yield of the tested heat susceptible variety, and noninvasive anthers and pollen formation in response to HT were associated with improved heat tolerance.

scholarly journals Abnormal Anther Development Leads to Lower Spikelet Fertility in Rice (Oryza Sativa L.) Under High Temperature During the Panicle Initiation Stage

2020 ◽  
Author(s):  
Qiuqian Hu ◽  
Kehui Cui ◽  
Wencheng Wang ◽  
Qifan Lu ◽  
Jianliang Huang ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
High Temperature ◽  
Grain Yield ◽  
Heat Tolerance ◽  
Pollen Viability ◽  
Anther Development ◽  
Spikelet Fertility ◽  
Anther Wall ◽  
Anther Dehiscence ◽  
Initiation Stage

Abstract Background: Decreased spikelet fertility is often responsible for reduction in grain yield in rice (Oryza sativa L.). In this study, two varieties with different levels of heat tolerance, Liangyoupeijiu (LYPJ, heat susceptible) and Shanyou63 (SY63, heat tolerant) were subjected to two temperature treatments for 28 days during the panicle initiation stage in temperature/relative humidity-controlled greenhouses: high temperature (HT; 37/27℃; day/night) and control temperature (CK; 31/27℃; day/night) to investigate changes in anther development under HT during panicle initiation and their relationship with spikelet fertility.Results: HT significantly decreased the grain yield of LYPJ by decreasing the number of spikelets per panicle and seed setting percentage. In addition, HT produced minor adverse effects in SY63. The decreased spikelet fertility was primarily attributed to decreased pollen viability and anther dehiscence, as well as poor pollen shedding of the anthers of LYPJ under HT. HT resulted in abnormal anther development (fewer vacuolated microspores, un-degraded tapetum, unevenly distributed Ubisch bodies) and malformation of pollen (obscure outline of the pollen exine with a collapsed bacula, disordered tectum, and no nexine of the pollen walls, uneven sporopollenin deposition on the surface of pollen grains) in LYPJ, which may have lowered pollen viability. Additionally, HT produced a compact knitted anther cuticle structure of the epidermis, an un-degraded septum, a thickened anther wall, unevenly distributed Ubisch bodies, and inhibition of the confluent locule, and these malformed structures may be partially responsible for the decreased anther dehiscence rate and reduced pollen shedding of the anthers in LYPJ. In contrast, the anther wall and pollen development of SY63 were not substantially changed under HT. Conclusions: Our results suggest that disturbed anther walls and pollen development are responsible for the reduced spikelet fertility and grain yield of the tested heat susceptible variety, and noninvasive anthers and pollen formation in response to HT were associated with improved heat tolerance.

Effects of high temperature at anthesis on spikelet fertility and grain weight in relation to floral positions within a panicle of rice (Oryza sativa L.)

2015 ◽  
Vol 66 (9) ◽  
pp. 922 ◽  
Author(s):  
Zhen-Zhen Cao ◽  
Qian Zhao ◽  
Fu-Deng Huang ◽  
Ke-Su Wei ◽  
Syed-Hassan-Raza Zaidi ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
High Temperature ◽  
Oryza Sativa L ◽  
Pollen Viability ◽  
Climatic Conditions ◽  
Grain Weight ◽  
Spikelet Fertility ◽  
Flowering Date

Responses in spikelet fertility and grain weight to high temperature (HT) at anthesis and the relation to floral positions within a panicle were investigated using two HT-susceptible cultivars (Xieqingzao and Gang46) and two HT-tolerant cultivars (Qianjiang3 and Haunghuazan) under well-controlled climatic conditions. Results showed that effects of HT at anthesis were more adverse for spikelet fertility than for grain weight. The cultivar-dependent difference in spikelet fertility response to HT was mainly attributed to the extent of decrease in pollen viability for HT exposure. HT at anthesis impelled the flowering date of the florets on the middle and lower parts within a panicle, thereby resulting in shortened duration to floret-opening date and relatively concentrated floret-blossoming date. Change in spikelet fertility induced by HT was more notable than that caused by different grain positions, and the effect of HT on pollen viability was independent of the floret positions on the rachides within a panicle. Positional differences in spikelet fertility and grain weight under the HT regime were closely associated with the duration of HT exposure, in addition to differences in competing ability for supply of assimilates after successful fertilisation.

Spikelet fertility and heat shock transcription factor (Hsf) gene responses to heat stress in tolerant and susceptible rice (Oryza sativa L.) genotypes

2019 ◽  
Vol 157 (04) ◽  
pp. 283-299 ◽  
Author(s):  
C. Malumpong ◽  
S. Cheabu ◽  
C. Mongkolsiriwatana ◽  
W. Detpittayanan ◽  
A. Vanavichit
Keyword(s):  
Heat Stress ◽  
Pollen Germination ◽  
Seed Set ◽  
Oryza Sativa L ◽  
Flag Leaf ◽  
Pollen Viability ◽  
Spikelet Fertility ◽  
Anther Dehiscence ◽  
Spikelet Sterility ◽  
Plant Parts

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.

Agronomic, physiological and molecular characterisation of rice mutants revealed the key role of reactive oxygen species and catalase in high-temperature stress tolerance

2020 ◽  
Vol 47 (5) ◽  
pp. 440 ◽  
Author(s):  
Syed Adeel Zafar ◽  
Amjad Hameed ◽  
Muhammad Ashraf ◽  
Abdus Salam Khan ◽  
Zia-ul- Qamar ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Heat Stress ◽  
High Temperature ◽  
Grain Yield ◽  
Temperature Stress ◽  
Heat Tolerance ◽  
High Temperature Stress ◽  
Oxygen Species ◽  
Selection Indices ◽  
Heat Tolerant

Climatic variations have increased the occurrence of heat stress during critical growth stages, which negatively affects grain yield in rice. Plants adapt to harsh environments, and particularly high-temperature stress, by regulating their physiological and biochemical processes, which are key tolerance mechanisms. The identification of heat-tolerant rice genotypes and reliable selection indices are crucial for rice improvement programs. Here, we evaluated the response of a rice mutant population for high-temperature stress at the seedling and reproductive stages based on agronomic, physiological and molecular indices. Estimates of variance components revealed significant differences (P < 0.001) among genotypes, treatments and their interactions for almost all traits. The principal component analysis showed significant diversity among genotypes and traits under high-temperature stress. The mutant HTT-121 was identified as the most heat-tolerant mutant with higher grain yield, panicle fertility, cell membrane thermo-stability (CMTS) and antioxidant enzyme levels under heat stress. Various seedling-based morpho-physiological traits (leaf fresh weight, relative water contents, malondialdehyde, CMTS) and biochemical traits (superoxide dismutase, catalase and hydrogen peroxide) explained variations in grain yield that could be used as selection indices for heat tolerance in rice during early growth. Notably, heat-sensitive mutants accumulated reactive oxygen species, reduced catalase activity and upregulated OsSRFP1 expression under heat stress, suggesting their key roles in regulating heat tolerance in rice. The heat-tolerant mutants identified in this study could be used in breeding programs and to develop mapping populations to unravel the underlying genetic architecture for heat-stress adaptability.

Some effects of heat waves on grain sorghum at the stage of head emergence

1969 ◽  
Vol 9 (41) ◽  
pp. 636 ◽  
Author(s):  
D Pasternak ◽  
GL Wilson
Keyword(s):  
High Temperature ◽  
Grain Yield ◽  
Seed Set ◽  
Heat Waves ◽  
Pollen Viability ◽  
Grain Sorghum ◽  
Heat Treatments ◽  
Grain Production ◽  
Dry Heat ◽  
Heat Application

Sorghum plants were exposed at head emergence to simulated heat waves for five days, and subsequent grain production observed. Comparisons were made between relatively dry heat (108�F, 41 per cent RH by day and 90�F, 53 per cent RH by night), more humid hot conditions (107�F, 70 per cent RH-90�F, 70 per cent RH), and ambient (81�F, 64 per cent RH-71�F, 85 per cent RH). Whole inflorescences or portions that had emerged before heat application were little affected, whereas most enclosed flowers were killed. High temperature was responsible, humidity having little effect. Grain yield depended on the resulting number of grains. There was some loss of pollen viability in the dry heat treatments, but not sufficient to affect seed set.

scholarly journals Genetic variations, heritability, heat tolerance indices and correlations studies for traits of bread wheat genotypes under high temperature

2019 ◽  
Vol 11 (5) ◽  
pp. 672-686
Author(s):  
Elfadil Mohamed Elbashier ◽  
Elfadil Mohammed Eltayeb Elbashier ◽  
Siddig Esa Idris2 ◽  
Wuletaw Tadesse ◽  
Izzat S.A. Tahir ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Grain Yield ◽  
Bread Wheat ◽  
Heat Tolerance ◽  
Agricultural Research ◽  
Canopy Temperature ◽  
Content Type ◽  
Wheat Genotypes ◽  
Tolerance Indices

PurposeThe purpose of this paper was to study the genetic variability, heritability, heat tolerance indices and phenotypic and genotypic correlation studies for traits of 250 elite International Center for Agricultural Research in the Dry Areas (ICARDA) bread wheat genotypes under high temperature in Wad Medani, Center in Sudan.Design/methodology/approachBread wheat is an important food on a global level and is used in the form of different products. High temperature associated with climate change is considered to be a detrimental stress in the future on world wheat production. A total of 10,250 bread wheat genotypes selected from different advanced yield trials introduction from ICARDA and three checks including were grown in two sowing dates (SODs) (1st and 2nd) 1st SOD heat stress and 2nd SOD non-stress at the Gezira Research Farm, of the Agricultural Research Corporation, Wad Medani, Sudan.FindingsAn alpha lattice design with two replications was used to assess the presence of phenotypic and genotypic variations of different traits, indices for heat stress and heat tolerance for 20 top genotypes and phenotypic and genotypic correlations. Analysis of variance revealed significant differences among genotypes for all the characters. A wide range, 944-4,016 kg/ha in the first SOD and 1,192-5,120 kg/ha in the second SOD, was found in grain yield. The average yield on the first SOD is less than that of the secondnd SOD by 717.7 kg/ha, as the maximum and minimum temperatures were reduced by 3ºC each in the second SOD when compared to the first SOD of the critical stage of crop growth shown.Research limitations/implicationsSimilar wide ranges were found in all morpho-physiological traits studied. High heritability in a broad sense was estimated for days to heading and maturity. Moderate heritability estimates found for grain yield ranged from 44 to 63.6 per cent, biomass ranged from 37.8 to 49.1 per cent and canopy temperature (CT) after heading ranged from 44.2 to 48 per cent for the first and secondnd SODs. The top 20 genotypes are better than the better check in the two sowing dates and seven genotypes (248, 139, 143, 27, 67, 192 and 152) were produced high grain yield under both 1st SOD and 2nd SOD.Practical implicationsThe same genotypes in addition to Imam (check) showed smaller tolerance (TOL) values, indicating that these genotypes had a smaller yield reduction under heat-stressed conditions and that they showed a higher heat stress susceptibility index (SSI). A smaller TOL and a higher SSI are favored. Both phenotypic and genotypic correlations of grain yield were positively and significantly correlated with biomass, harvest index, number of spikes/m2, number of seeds/spike and days to heading and maturity in both SODs and negatively and significantly correlated with canopy temperature before and after heading in both SODs.Originality/valueGenetic variations, heritability, heat tolerance indices and correlation studies for traits of bread wheat genotypes under high temperature

scholarly journals Combining ability and heterosis prediction for grain yield of parental lines and hybrids for heat tolerance in rice (Oryza sativa L.)

2017 ◽  
Vol 12 (Special-5) ◽  
pp. 1213-1221
Author(s):  
N. SRAVAN RAJU ◽  
P. SENGUTTUVEL ◽  
A.S. HARI PRASAD ◽  
P. BEULAH ◽  
P. NAGANNA ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Grain Yield ◽  
Heat Tolerance ◽  
Combining Ability ◽  
Oryza Sativa L ◽  
Heterosis Prediction ◽  
Parental Lines

scholarly journals Assessment of Morphometric Diversity for Yield and Yield Attributing Traits in Rice (Oryza sativa L.) for Tolerance to Heat Stress

2020 ◽  
pp. 29-49
Author(s):  
S. Sandeep ◽  
M. Sujatha ◽  
L. V. Subbarao ◽  
C. N. Neeraja
Keyword(s):  
Principal Component Analysis ◽  
Oryza Sativa ◽  
Heat Stress ◽  
Oryza Sativa L ◽  
Pollen Viability ◽  
Principal Component ◽  
Component Analysis ◽  
Spikelet Fertility ◽  
Breeding Programmes ◽  
Heat Tolerant

The present investigation entitled “Assessment of morphometric diversity for yield and yield attributing traits in rice (Oryza sativa L.) for tolerance to heat stress” was carried out with objective of assessing genetic divergence in 200 germplasm of rice for eleven characters at ICRISAT, Patencheru, Hyderabad. The genotypes were grouped into fifteen clusters in Tocher’s method, cluster analysis and principal component analysis, out of the 11 characters studied, number of grains per panicle, plant height, pollen viability and spikelet fertility contributed 96.73 per cent of the total divergence and these traits were found to be important potent factors for genetic differentiation in genotypes. Principal component analysis identified five principal components, which contributed for 78.66 percent % of cumulative variance. The overall results of the study revealed that crossing using the genotypes under cluster V and XI and cluster XI and XIII could be exploited by hybridization programme to yield good recombinants because they had maximum inter cluster distance and possessing high genetic diversity for the characters viz. panicle length, number of grains per panicle and single plant yield. The genotypes of cluster I, II, IV, VI, VII, VIII, XI, XII and XIII showed high spikelet fertility percentage. Hence the genotypes of these clusters can be used in breeding programmes for development of heat tolerant varieties. Euclidean2 method indicated that genotypes of cluster III and IX exhibited high spikelet fertility percentage which can be utilized in development of heat tolerant cultivars. The results of principal component analysis revealed that genotypes of cluster I, cluster IV, cluster V, cluster VIII, cluster IX, cluster XI, cluster XII and cluster XV exhibited highest spikelet fertility percentage. Hence, the genotypes of the clusters can be used in breeding programmes for the development of heat tolerant varieties. 

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