Rice stem borer(Chilo agamemnon Bles.)is a primary insect pest of rice and is a major limiting factor to rice production.Breeding for insect-resistant crop varieties has been an economic way of integrated pest managem...Rice stem borer(Chilo agamemnon Bles.)is a primary insect pest of rice and is a major limiting factor to rice production.Breeding for insect-resistant crop varieties has been an economic way of integrated pest management(IPM)as it offers a viable and ecologically acceptable approach.This study was aimed to evaluate rice genotypes for their resistance against rice stem borer.Seven parental genotypes with twenty one F1 crosses were evaluated for genotypic variation in field experiments.Analysis of variance revealed significant differences for the studied traits in almost all crosses and parents.In addition,the mean squares of parents versus their crosses were signifi-cant for stem borer resistance and other associated traits.Moreover,both general combining ability(GCA)and specific combining ability(SCA)variances were highly significant for all characters studied in the F1 generation.Based on GCA,4 genotypes(Sakha101,Gz6903-3-4-2-1,Gz9577-4-1-1 and Hassawi)exhibited highly significant negative values for stem borer resistance(–0.53,–1.06,–0.18 and–0.49,respectively)indicating they are the best combiners for stem borer resistance.Based on SCA analysis,nine cross combinations showed highly significant negative effects for stem borer resistance.Similarly,the cross Giza178Hassawi was the best combination with significantly highest value for early maturity.In addition,seven crosses showed highly significant negative SCA for plant height trait.On the other hand,for panicle length,number of primary branches/panicle,panicle weight and 1000-grain weight,seven,four,eight and six crosses showed highly significant positive SCA,respectively.The result further revealed that the non-additive dominance genetic variance was higher than the additive variance for all evaluated traits indicating that non-additive genetic variances have a role in their inheritance.The broad-sense heritability estimates were high for all the studied traits.The stem borer resistance was significantly correlated with panicle weight and 1000-grain weight,which also showed a highly significant correlation with grain yield/plant.Thus these traits can be effectively employed in a breeding program to confer resistance against stem borer infestation in rice.It was further supported by biplot analysis,which clustered these potentially important traits into two quadrants showing their importance in any future breeding program to control stem borer infestation.This study has contributed valuable information for evaluation of genetic diversity in the local rice germplasm and its utilization in futuristic rice genetic improvement programs.展开更多
基金the Deputyship for Research&Innovation,Ministry of Education in Saudi Arabia for funding this research work through the Project No.IFT20004.
文摘Rice stem borer(Chilo agamemnon Bles.)is a primary insect pest of rice and is a major limiting factor to rice production.Breeding for insect-resistant crop varieties has been an economic way of integrated pest management(IPM)as it offers a viable and ecologically acceptable approach.This study was aimed to evaluate rice genotypes for their resistance against rice stem borer.Seven parental genotypes with twenty one F1 crosses were evaluated for genotypic variation in field experiments.Analysis of variance revealed significant differences for the studied traits in almost all crosses and parents.In addition,the mean squares of parents versus their crosses were signifi-cant for stem borer resistance and other associated traits.Moreover,both general combining ability(GCA)and specific combining ability(SCA)variances were highly significant for all characters studied in the F1 generation.Based on GCA,4 genotypes(Sakha101,Gz6903-3-4-2-1,Gz9577-4-1-1 and Hassawi)exhibited highly significant negative values for stem borer resistance(–0.53,–1.06,–0.18 and–0.49,respectively)indicating they are the best combiners for stem borer resistance.Based on SCA analysis,nine cross combinations showed highly significant negative effects for stem borer resistance.Similarly,the cross Giza178Hassawi was the best combination with significantly highest value for early maturity.In addition,seven crosses showed highly significant negative SCA for plant height trait.On the other hand,for panicle length,number of primary branches/panicle,panicle weight and 1000-grain weight,seven,four,eight and six crosses showed highly significant positive SCA,respectively.The result further revealed that the non-additive dominance genetic variance was higher than the additive variance for all evaluated traits indicating that non-additive genetic variances have a role in their inheritance.The broad-sense heritability estimates were high for all the studied traits.The stem borer resistance was significantly correlated with panicle weight and 1000-grain weight,which also showed a highly significant correlation with grain yield/plant.Thus these traits can be effectively employed in a breeding program to confer resistance against stem borer infestation in rice.It was further supported by biplot analysis,which clustered these potentially important traits into two quadrants showing their importance in any future breeding program to control stem borer infestation.This study has contributed valuable information for evaluation of genetic diversity in the local rice germplasm and its utilization in futuristic rice genetic improvement programs.
