scholarly journals Enclosed stigma contributes to higher spikelet fertility for rice (Oryza sativa L.) subjected to heat stress

2019 ◽  
Vol 7 (3) ◽  
pp. 335-349 ◽  
Author(s):  
Chao Wu ◽  
Kehui Cui ◽  
Qiuqian Hu ◽  
Wencheng Wang ◽  
Lixiao Nie ◽  
...  
Author(s):  
S. Sandeep ◽  
M. Sujatha ◽  
L. V. Subbarao ◽  
C. N. Neeraja

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. 


2021 ◽  
Author(s):  
Masahiro Yamaguchi ◽  
Shoma Kamiya ◽  
Dai Kokubun ◽  
Tomoki Nakayama ◽  
Tetsushi Yonekura ◽  
...  

Abstract Two Japanese cultivars of rice (Oryza sativa L.), Hinohikari and Nikomaru, were planted using potting soil on June 13, 2018, and were exposed to elevated CO2 from June 26 to October 9 using open-top chambers. The study was conducted in Nagasaki, in the Kyushu region of Japan, where the air temperature is relatively high. There were two treatments: ambient CO2 treatment with approximately 400 µmol mol–1 (ppm) CO2, and elevated CO2 treatment with approximately 550 ppm CO2. The elevated CO2 treatment significantly increased the net photosynthetic rate and whole-plant dry mass of the two rice cultivars. However, this treatment did not produce significant effects on grain yield and adversely affected grain appearance quality of both cultivars. Among the yield components, spikelet fertility was significantly reduced by exposure to elevated CO2. These adverse effects were typical manifestations of heat stress in rice. Even under ambient CO2 treatment, there was relatively low spikelet fertility and grain appearance quality, because air temperature during the cultivation period was higher than the standard climatological normal of air temperature. Furthermore, under elevated CO2 treatment, significant reductions in transpiration rate of flag leaves were observed during the flowering period. This may cause an increase in temperature of the canopy, including the panicle, and induce heat stress. These results suggest that elevated CO2 could induce heat stress in rice via reduction in transpiration under high air temperature conditions.


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.


2005 ◽  
Vol 86 (2) ◽  
pp. 97-106 ◽  
Author(s):  
CHUNMING WANG ◽  
CHENGSONG ZHU ◽  
HUQU ZHAI ◽  
JIANMIN WAN

Markers with segregation ratio distortion are commonly observed in data sets used for quantitative trait locus (QTL) mapping. In this study, a multipoint method of maximum likelihood (ML) was newly developed to estimate the positions and effects of the segregation distortion loci (SDLs) in two F2 populations of rice (Oryza sativa L.), i.e. Taichung65/Bhadua (TB; japonica–indica cross) and CPSLO17/W207-2 (CW; japonica–japonica). Of the four parents, W207-2 and Bhadua were found to be spikelet semi-sterile and stably inherited through selfing, and spikelet fertility segregated in the two populations. Therefore, recombination frequencies were recalculated after mapping the SDLs by using the multipoint method, and the molecular linkage maps of the two F2 populations were constructed to detect QTLs underlying spikelet fertility. As a result, five SDLs in the TB population were mapped on chromosomes 1, 3, 8 and 9, respectively. Two major QTLs underlying spikelet fertility, namely qSS-6a and qSS-8a, were detected on chromosomes 6 and 8, respectively. In the CW population, a total of 12 SDLs were detected on all 12 chromosomes except 1, 5, 7 and 11. Three QTLs underlying spikelet sterility, namely qSS-2, qSS-6b and qSS-8b on chromosomes 2, 6 and 8, were determined on the whole genome scale. Interestingly, both qSS-6a and qSS-6b, detected in the two F2 populations respectively, were located on a similar position as the S5 gene on chromosome 6; while qSS-8a and qSS-8b were also simultaneously detected on similar positions of the short arm of chromosome 8 in the two populations, which should be a new sterility gene showing the same type of zygotic selection.


2017 ◽  
Vol 216 ◽  
pp. 52-57 ◽  
Author(s):  
Chetphilin Suriyasak ◽  
Keisuke Harano ◽  
Koichiro Tanamachi ◽  
Kazuhiro Matsuo ◽  
Aina Tamada ◽  
...  

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