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. 

scholarly journals GENETIC DIVERSITY AND PARENTS SELECTION FROM EXOTIC RICE (Oryza sativa L.) GERMPLASM

2012 ◽  
Vol 25 (1) ◽  
pp. 11-16
Author(s):  
A. A. Mamun ◽  
N. A. Ivy ◽  
M. G. Rasul ◽  
M. M. Hossain
Keyword(s):  
Genetic Diversity ◽  
Principal Component Analysis ◽  
Cluster Analysis ◽  
Oryza Sativa ◽  
Oryza Sativa L ◽  
Principal Component ◽  
Component Analysis ◽  
Rice Genotypes ◽  
Total Divergence ◽  
Five Axes

Genetic divergence among fifty exotic rice genotypes along with two check varieties were estimated using D2 and principal component analysis. The study was undertaken to select suitable donor parents for use in improved breeding program of Bangabandhu Sheikh Mujibur Rahman Agricultural University in 2009. Principal component analysis (PCA) revealed that the first five axes accounted for 58.10% of the total variation. As per cluster analysis, the genotypes were grouped into seven clusters consisting 11, 16, 7, 11, 1, 2 and 4 genotypes which revealed that there exist considerable diversity among the genotypes. Considering the magnitude of genetic distance, contribution of different characters towards the total divergence and magnitude of cluster means for different characters, the genotypes RG-BU-08-057, 61, 65, 67, 69, 71, 85, 86, 88, 94, 96, 98 and 99 might be selected as a suitable parent for future hybridization program.DOI: http://dx.doi.org/10.3329/bjpbg.v25i1.17007

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.

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