جستجوی مقالات مرتبط با کلیدواژه « سرکوسپورا » در نشریات گروه « زراعت »

In order to determine the most important traits influencing root yield and sugar content of autumn-sown sugar beet monogerm O-type lines, 49 genotypes (O-types and hybrids) were evaluated in a triple lattice design with three replicates at Safiabad Agricultural Research Center, Dezful, Iran in 2008-2009. Following an analysis of variance, statistical analyses such as simple correlation coefficients among the traits were administered on treatment means. Factor analysis divided all the studied parameters into five factors: white sugar content, yield, root morphological characteristics, resistance to bolting and Cercospora leaf spot. Root diameter, resistance to Cercospora, crown height, root shape, alpha-amino nitrogen, potassium and extraction coefficient of sugar were identified as the most important traits in stepwise regression analysis for root yield as the dependent variable. In forward regression analysis for sugar content as the dependent variable, the most important traits were found to be molassed sugar, crown height and resistance to bolting, respectively. Path analysis indicated that root diameter, root shape and alpha-amino nitrogen had direct positive effects and cercospora resistance, crown height, potassium and white sugar content had direct negative effects on root yield. Also, the direct effect of crown height on sugar content was positive and that of molassed sugar and cercospora resistance was negative. Cluster analysis demonstrated that the genotypes of cluster 2 were superior in the traits affecting root yield, whereas the genotypes of cluster 1 were superior with respect to the traits influencing white sugar content and extraction coefficient of sugar. Therefore, the genotypes of the latter cluster could be used to increase white sugar content and extraction coefficient of sugar and hence decrease the impurities such as sodium, potassium and alpha amino nitrogen.

To evaluate general and specific combining ability for resistance to bolting and Cercospora leaf spot, 36 hybrids derived from crosses between 9 sugar beet lines along with four checks were planted in Safiabad Agricultural Research Center (Dezful) in 2008-2009. The experimental design was a triple lattice design with three replications. Analysis of variance showed significant differences among genotypes for all of the traits with exception of sugar content, sodium, white sugar content and purity. Analysis of combining ability using Griffing's method II indicated that general combining ability of the lines was significant for all of the traits in probability level of 1%. Also, specific combining ability was significant for root yield, sugar yield, white sugar yield and potassium in probability level of 1% and for resistance to bolting and Cercospora leaf spot in probability level of 5%. In general, both additive and non-additive effects were effective in controlling the resistance to Cercospora and bolting, root yield, sugar yield and white sugar yield. However, resistance to bolting, root yield, sugar yield and white sugar yield were found to be mainly determined by the non-additive gene effects. The best parent for resistance to Cercospora and bolting was RR607, however, its root yield was not suitable. The best hybrid for resistance to Cercospora, root yield, sugar yield and white sugar yield was F1 of RR607×452. Furthermore, the best cross for resistance to bolting was SB-FIROZ×261. Nonetheless, cross of RR607×436 produced the best hybrid for resistance to bolting and Cercospora.