The inheritance of resistance to blue mold (Peronospora tabacinaAdam) in two cultivars of tobacco (Nicotiana tabacumL.)
✍ Scribed by A. Marani; G. Fishler; A. Amirav
- Publisher
- Springer
- Year
- 1972
- Tongue
- English
- Weight
- 578 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0014-2336
No coin nor oath required. For personal study only.
✦ Synopsis
Two blue-mold resistant cultivars of Nicotiuna tabacum L. were crossed with each other and with the susceptible Israeli local cultivar Mikhal. F1, F, and F3 progenies of these crosses, F1 and Fz of backcrosses and the parental varieties were grown in a series of experiments, in which the seedlings were exposed to heavy natural infection with Peronospora tabacina ADAM. The genetic basis of resistance was found to be identical in the two resistant strains Bel-61-10 and Chemical mutant. A single dominant major gene determined the segregation of resistance versus susceptibility in the crosses of these strains with Mikhal. The level of resistance of resistant segregates was shifted by environment and by quantitatively modifying genes. The index of resistance, which was calculated as a weighted mean of the degree of blue-mold expression of the resistant segregates, differed in the generations of cross progeny. This could be explained by the different expected levels of the modifying genes in these generations. Heritability of the index of resistance was calculated by parent-offspring regression and it was found to be 0.542 in the F3 and 0.227 in F, backcross progenies.