RESISTANCE DEGREE OF SOME SWEET PEPPER GENOTYPES TO POWDERY MILDEW | ||||
| Egyptian Journal of Plant Breeding | ||||
| Volume 23, Issue 4, March and April 2019, Page 471-481 PDF (478.41 K) | ||||
| Document Type: Original research | ||||
| DOI: 10.12816/ejpb.2019.344250 | ||||
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| Abstract | ||||
| Resistance degree of some sweet pepper genotypes to powdery mildew caused by Leveillula taurica was studied under artificial conditions. The aim of this study was to determine resistant lines or crosses used as new pepper cultivars or hybrids in commercial production and obtain more information about the mode of inheritance of powdery mildew disease. The evaluated genotypes were nineteen new breeding lines, 10 F1 crosses with their parental lines and six populations, i.e., the two parents, F1, F2, Bc1 and Bc2 of only one cross. The experimental work was carried out at Experimental Farm of Faculty of Agriculture, Menoufia University during three seasons. A randomized complete block design (RCBD) with three replicates was used. Data were recorded and statistically analyzed. Some genetical parameters were estimated. The obtained data showed significant differences among the studied lines in average severity of infection. Based on degree of resistance the lines were classified into three groups, i.e., moderate resistance, moderate susceptible and susceptible. The best lines were L-4, L-15, L-19 and L-17, since they showed the lowest average severity of infection (1.9, 2.4, 4.2 and 4.3%) and can be used as resistant cultivars or resistance source in breeding for powdery mildew. Estimated average degree of heterosis for all resulted F1 crosses indicated that the character is controlled by additive gene actions with slight dominance to the susceptible parent. For the mean generation analysis of the cross (L-9 × L-19) the high estimated additive variance ( 27.98%) compared with the dominance one ( 12.62%) and the high estimated broad and narrow sense heritabilities ( 92.7 % and 63.9%, respectively ) showed that a large amount of variance was due to the genetical variance, and additive variance was more important in the inheritance of the trait. These results indicated significant improvement of resistance to powdery mildew can be realized by selection. The high estimated value of genetic advance under selection (DG %) support that. In general, it could be concluded that the resistance to powdery mildew may be controlled by a single pair of genes with additive gene action and slight dominance of the susceptible gene. | ||||
| Keywords | ||||
| Leveillula taurica; Capsicum annuum; Gene action; Heritability; Heterosis; Powdery mildew; Severity of infection; Selection | ||||
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