scholarly journals Combining ability and heterosis for earliness characters in line×tester population of Gossypium hirsutum L.

Hereditas ◽  
2007 ◽  
Vol 144 (5) ◽  
pp. 185-190 ◽  
Author(s):  
Sema Basbag ◽  
Remzi Ekinci ◽  
Oktay Gencer
Keyword(s):  
Gossypium Hirsutum ◽  
Combining Ability ◽  
Gossypium Hirsutum L

Thrips (Thysanoptera: Thripidae) Tolerance in Cotton: Sources and Heritability

1997 ◽  
Vol 32 (4) ◽  
pp. 460-471 ◽  
Author(s):  
Daryl T. Bowman ◽  
Jack C. McCarty
Keyword(s):  
North Carolina ◽  
Gossypium Hirsutum ◽  
Combining Ability ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
General Combining Ability ◽  
Sources Of Resistance ◽  
Gossypium Hirsutum L ◽  
F2 Generation ◽  
F1 Generation

Thrips (Thysanoptera: Thripidae) resistance or tolerance in cotton, Gossypium hirsutum L., is often associated with extreme pubescence. This is undesirable because hairy (pubescent) plants tend to have more trash in harvested lint which reduces the price received by growers. Two other possible sources of resistance include gossypol and thick lower epidermal cells, the latter has been found in G. barbadense L. Five G. barbadense genotypes were mated in a North Carolina Design II to 4 upland cultivars to evaluate combining ability. In addition, 90 converted racestocks were screened for tolerance to thrips. Experiments were designed to evaluate tolerance or resistance by comparing plots with and without thrips. Two G. barbadense parents had tolerance to thrips while two upland cultivars also exhibited tolerance. In the F1 generation, general combining ability was significant for thrips damage ratings among the G. barbadense parents. In the F2 generation, all characters exhibited specific combining ability. Thus, non-additive genetic variance predominates measures of thrips tolerance.

scholarly journals Combining Ability Analysis of Heat Tolerance in Gossypium hirsutum L.

2011 ◽  
Vol 41 (No. 1) ◽  
pp. 23-28 ◽  
Author(s):  
T. Azhar M ◽  
A. Khan A ◽  
A. Khan I
Keyword(s):  
Gossypium Hirsutum ◽  
Heat Tolerance ◽  
Combining Ability ◽  
Specific Combining Ability ◽  
Gossypium Hirsutum L ◽  
Gene Effects ◽  
Combining Ability Analysis ◽  
Additive Gene ◽  
Significant Comparison ◽  
Efficient Transfer

In order to study the genetic control of heat tolerance, four varieties/lines of Gossypium hirsutum L., namely MNH-554, Cocker-304, Delcerro and Albacala (71) 1190, were crossed in all possible combinations. Heat tolerance of 12 hybrids and their parents was measured at reproductive phase using an electrolyte leakage technique. The genetic analysis of the data showed significant effects of specific combining ability and reciprocals, but the effect of general combining ability appeared to be non-significant. Comparison of the parents for heat tolerance revealed that Delcerro and MNH-554 were the best general combiners for the character. The crosses Cocker-304 × Delcerro and Albacala (71) 1190 × MNH-554 were determined as the best combinations for heat tolerance and they involved one good general combiner as a parent. Significant effects due to specific combining ability indicated the importance of non-additive gene effects controlling heat tolerance. This information suggests that development of heat tolerance in the present plant material may be difficult; therefore it is necessary to design a specific breeding programme for efficient transfer of the trait.  

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