Estimating Breeding Value of Agronomic Traits in Oriental Tobacco Genotypes under Broomrape Stress and Normal Conditions

In a breeding program, it is important to find out information about the genes action, because knowledge in this field could help the researchers in their crossing programs and realizing effective selection. In this study, breeding values of different agronomic traits in oriental tobacco were predicted using the best linear unbiased prediction (BLUP) procedure. For this purpose, 89 tobacco genotypes were evaluated in a randomized complete block design with three replications under normal (without broomrape) and stress (with broomrape) conditions at Urmia Tobacco Research Centre, during two successive years. Broomrape stress was applied by mixing 0.06 gr broomrape seed with soil in pots. C.H.T.209.12e × F.K.40-1 genotype had high yield under both normal and broomrape stress conditions and was one of the desirable genotypes in terms of yield tolerance and stability index. The Rustica genotype was the best genotype in terms of the breeding value of most of studied traits in both normal and broomrape stress conditions. The result from cluster analysis based on the breeding values of the studied traits showed that, tobacco genotypes were divided into 6 and 5 groups in normal and broomrape stress conditions, respectively; but the distribution of genotypes within the groups was different depending on the conditions. The highest heritability was observed for root fresh weight under normal condition and for leaf fresh weight under broomrape stress conditionss. The results showed that a genotype with good phenotypic performance may have low breeding value. Therefore, considering breeding value information along with phenotypic mean of traits can increase the efficiency of breeding programs.