scholarly journals COMBINING ABILITY AND GENE ACTION FOR FRUIT YIELD AND HEAT TOLERANCE IN TOMATO (Lycopersicon lycopersicum Mill.) UNDER HEAT STRESS CONDITIONS.

2016 ◽  
Vol 4 (7) ◽  
pp. 89-96
Author(s):  
Habu S.H. ◽  
◽  
Afolayan S.O. ◽  
Yaduma J.J. ◽  
Idris B.A. ◽  
...  
Author(s):  
Chiseche Mwanza ◽  
Mebelo Mataa ◽  
Langa Tembo

Maize is an important cereal in sub-Saharan Africa. Its production is however hampered by both biotic and abiotic factors. Among the abiotic factors, heat stress has been reported to cause yield losses. The objective of this study was therefore to identify tolerant genotypes to heat stress and determine the type of gene action conditioning heat tolerance in tropical maize. To achieve these objectives, five maize inbred lines (L2 [P1]; DTS 6,36 [P2]; L5527 [P3]; DTS 6,6 [P4] and DTS 6,92 [P5]) were mated in a 5 x 5 half diallel. Their progeny were evaluated at a heat prone site (Lusitu) and at the University of Zambia (UNZA), a control site. The experiment was laid as a randomised complete block design with two replications in each site. Highly significant differences (P ≤ 0.01) were obtained among genotypes in Lusitu with regards to all measured parameters. The crosses[P2 (DTS 6,36) x P4 (DTS 6,6)] and [P4 (DTS 6,6) x P5 (DTS 6,92)]were identified as tolerant genotypes to heat stress. Further analysis showed that the general combining ability (GCA) effects for parent P4 (DTS 6, 6) and P3 (L5527) were positively and negatively significantly different (P ≤ 0.01) from zero respectively with regards to all measured parameters. On the other hand, crosses [P1 (L2) x P3 (L5527)] & [P4 (DTS 6,6) x P5 (DTS 6,92)]were found to possess desirable significant (P ≤ 0.05) specific combining ability (SCA)effects from zero. The results of baker’s ratio obtained for responseto heat stress for all secondary traits measured were found to be greater than 0.88. This implied that additive gene action was more important in conditioning the response of these traits to heat tolerance.


2016 ◽  
Vol 10 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Uttam Bhattarai ◽  
Pranab Talukdar ◽  
Akashi Sharma ◽  
Ranjan Das

2021 ◽  
Vol 72 (4) ◽  
pp. 280
Author(s):  
Mohammad Moradi ◽  
Hamid Dehghani ◽  
Sied Zabihallah Ravari

Improvement of tomato (Lycopersicon esculentum L.) for growth in saline soils is a major goal of tomato breeders. The aim of this study was to identify the genetic combining ability and genetics of salinity tolerance in tomato. Plant materials were grown under normal (NG) and salinity stress (SSG) conditions. Results showed that the genetic controlling mechanism of salinity-related traits and fruit weight is complex and that all genetic components of additive, non-additive and maternal are involved. The nature of gene action for fruit weight and salinity-related traits was significantly affected by salinity stress. Dominance and additive gene action were predominant under NG and SSG, respectively. Under NG, the best general combiner parent for fruit weight was P3 (salt-tolerant with moderate fruit yield). Under SSG, P1 (highly salt-tolerant with low fruit yield) was the best general combiner parent for fruit weight and exhibited high genetic combining ability for K+/Na+, lipoxygenase activity, proline, relative water content, total carbohydrate and cell membrane stability. With the high frequency of genes effective in salt tolerance, the P1 parent appeared as the best specific mating partner with other parents under SSG. Simultaneous selection for fruit weight and surrogate traits (cell membrane stability, proline and relative water content) in a population derived from the P1 × P5 (susceptible with high fruit yield) cross could result in a salt-tolerant tomato genotype.


2021 ◽  
Vol 50 (3) ◽  
pp. 659-669
Author(s):  
Neha Rani ◽  
Ram Balak Prasad Nirala ◽  
Awadhesh Kumar Pal ◽  
Tushar Ranjan

Investigation was carried out to ascertain the genetic architecture for heat tolerance and yield components from diallel crosses in maize (Zea mays L.). The combining ability in both the normal and heat stress conditions revealed highly significant mean squares due to general combining ability (GCA) and specific combining ability (SCA) in both the direct and reciprocal crosses for all the characters except for anthesis-silking interval in normal condition of the reciprocal crosses. Estimate of components of variance for 13 characters revealed higher SCA variance than that of GCA and reciprocal crosses for all the characters. CML 411 was good general combiner for grain yield in both the conditions, whereas, CML 306 and CML 307 were good general combiners in heat stress condition, and CML 164, CML 304 and CML 305 were average general combiners in normal condition. On the basis of high yield, high SCA and at least high GCA of seed parent, the CML 411*CML 305 and CML 411*CML 307 were identified as promising hybrids for normal and heat stress conditions, respectively. Bangladesh J. Bot. 50(3): 659-669, 2021 (September)


1970 ◽  
Vol 23 (2) ◽  
pp. 1-6
Author(s):  
R Podder ◽  
MG Rasul ◽  
AKMA Islam ◽  
Mak Mian ◽  
JU Ahmed

A half diallel set of five parents and their 10 F1’s were studied to determine the combining ability and magnitude of heterosis for eight important characters in snakegourd at the experimental field of Bangabandhu Sheikh Mujibur Rahman Agricultural University during April to July, 2004. Combining ability analysis revealed that both general and specific combining ability variances were significant for all the characters except fruit diameter and fruit yield per plant. Predominance of additive gene action was noted for all the characters except days to first female flower where non-additive gene action was predominant. Parent P1 was the best general combiner for fruit yield and some yield contributing characters. Among the crosses P2  X P3, P1  X P2 and P1  X P4 were the best specific combiner for fruit yield and some of yield contributing characters. Both positive and negative heterosis was obtained of which few hybrids showed desirable and significant values. P2  X P5 showed the highest significant mid parental heterotic value for earliness and high yield whereas, P1  X P2, P2  X P3, P2  X P5 and P3  X P4 showed the highest significant better parent heterotic effect for earliness and high yield. Key words: Snakegourd (Trichosanthes cucurminata L.); combining ability; heterosis; fruit yieldDOI: http://dx.doi.org/10.3329/bjpbg.v23i2.9318 Bangladesh J. Pl. Breed. Genet., 23(2): 1-6, 2010


2021 ◽  
Vol 13 (5) ◽  
pp. 2972
Author(s):  
Muhammad Waheed Riaz ◽  
Liu Yang ◽  
Muhammad Irfan Yousaf ◽  
Abdul Sami ◽  
Xu Dong Mei ◽  
...  

Heat stress is one of the major threats to wheat production in many wheat-growing areas of the world as it causes severe yield loss at the reproductive stage. In the current study, 28 crosses were developed using 11 parental lines, including 7 female lines and 4 male testers following line × tester matting design in 2018–2019. Twenty-eight crosses along with their 11 parental lines were sown in a randomized complete block design in triplicate under optimal and heat stress conditions. Fifteen different morpho-physiological and grain quality parameters were recorded at different growth stages. Analysis of variance illustrated the presence of highly significant differences among wheat genotypes for all traits under both optimal and heat stress conditions. The results of combining ability unveiled the predominant role of non-additive gene action in the inheritance of almost all the studied traits under both conditions. Among parents, 3 parental lines WL-27, WT-39, and WL-57 showed good combining ability under both normal and heat stress conditions. Among crosses, WL-8 × WT-17, WL-37 × WT-17, WL-7 × WT-39, and WL-37 × WT-39 portrayed the highest specific combining ability effects for grain yield and its related traits under optimal as well as heat stress conditions. Biplot and cluster analysis confirmed the results of general and specific combining ability by showing that these wheat crosses belonged to a highly productive and heat tolerant cluster. Correlation analysis revealed a significantly positive correlation of grain yield with net photosynthetic rate, thousand-grain rate, and the number of grains per spike. The designated parental lines and their crosses were selected for future breeding programs in the development of heat resilient, climate-smart wheat genotypes.


2019 ◽  
Vol 13 (1) ◽  
pp. 34-43
Author(s):  
Swapan Chakrabarty ◽  
A. K. M. Aminul Islam ◽  
M. A. Khaleque Mian ◽  
Tofayel Ahamed

Introduction: An experiment was conducted to study combining ability and heterosis for yield and related traits in chili during November 2015 to September 2017. Materials and Methods: The experimental material consisted of six parents and their fifteen F1’s developed by half diallel mating design. Analysis of variance for combining ability exhibited significant General and Specific Combining Ability (GCA and SCA) effects for all the characters studied. Results: The SCA variance was higher than GCA variance for all the traits except ten fresh fruit weight, fruit length and fruit width indicating the predominance of non-additive type of gene action. The parents P1 and P6 were identified as the best general combiners and the hybrids P1×P6, P1×P4 and P2×P5 were identified as the best specific combinations for fresh fruit yield per plant and related traits. The hybrids P1×P6, P1×P4 and P3×P6 showed significant average heterosis and heterobeltiosis for fresh fruit yield per plant and its related traits. (H1/D)0.5 ratio indicated partial dominance effect of genes for all the traits. Conclusion: Therefore, it may be possible to take advantages of better heterotic effects to be fixed in the later generations to facilitate further selection and best specific combinations for development of the hybrid variety of chili which can help to increase the total production in Bangladesh.


2019 ◽  
Vol 46 (1) ◽  
pp. 44 ◽  
Author(s):  
Damodar Poudyal ◽  
Eva Rosenqvist ◽  
Carl-Otto Ottosen

This study aimed to phenotype young tomato (Solanum lycopersicum L.) plants for heat tolerance by measuring Fv/Fm after short-term heat treatments in climate chambers and selected sensitive (low Fv/Fm) and tolerant (high Fv/Fm) cultivars to investigate their in-field performance. Twenty-eight genotypes were phenotyped at 40:28°C for 2 days in climate chambers. A second screening (four high Fv/Fm and four low Fv/Fm genotypes) was conducted for 4 days at 38:28°C, followed by 5 days’ recovery (26:20°C). The tolerant genotypes maintained high net photosynthesis (PN) and increased stomatal conductance (gs) at 38°C, allowing better leaf cooling. Sensitive genotypes had lower Fv/Fm and PN at 38°C, and gs increased less than in the tolerant group, reducing leaf cooling. Under controlled conditions, all eight genotypes had the same plant size and pollen viability, but after heat stress, plant size and pollen viability reduced dramatically in the sensitive group. Two tolerant and two sensitive genotypes were grown in the field during a heat wave (38:26°C). Tolerant genotypes accumulated more biomass, had a lower heat injury index and higher fruit yield. To our knowledge, this is the first time screening for heat tolerance by Fv/Fm in climate chambers was verified by a field trial under natural heat stress. The differences after heat stress in controlled environments were comparable to those in yield between tolerant and sensitive groups under heat stress in the field. The results suggest that Fv/Fm is effective for early detection of heat tolerance, and screening seedlings for heat sensitivity can speed crop improvement.


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