Genetic analysis of anther culture response and identification of QTLs associated with response traits in wheat (Triticum aestivum L.).

Anther culture is the most effective tool for doubled haploid production of wheat. This investigation was conducted to estimate genetic parameters of anther culture response in wheat and identification of putative Quantitative trait loci (QTLs) associated with response traits. Two varieties of wheat, namely ICR-DH (P1) and Sle 1 × 15 (P2) and their F1 and F2 progenies were used in the present investigation to estimate genetic parameters of anther culture response. Two molecular marker systems, SRAP and SSR markers were used to detect the polymorphism between two anther donor parents. Single marker analysis (SMA) and Composite interval mapping (CIM) were used to localize the putative QTL associated with four anther culture response in wheat using 100 plants of F2 population derived from F1 cross 'ICR-DH' × 'Sel 1 × 15'. Analyses of variance indicated significant differences between four populations (P1, P2, F1 and F2) for callus induction (CAL), number of green plants per 100 anther (GR), number of albino plant per 100 anther (AR) and total regenerated plants per 100 anther (TR). The additive effects were more important than dominance effects in controlling these traits. The two molecular marker systems were sufficient in detecting polymorphism between two parents. Thirty two putative QTLs were detected on eight linkage groups. Our study indicated that the additive effects of genes and detection of new QTLs permit marker-assisted selection of genotypes with high green plantlet regeneration efficiency in anther culture, and therefore favor efficient use of anther culture in wheat breeding programs.

Genetic Diversity Studies and Identification of Molecular and Biochemical Markers Associated with Fusarium Wilt Resistance in Cultivated Faba Bean (Vicia faba).

Faba bean (Vicia faba L.) is one of the most important legume crops in Egypt. However, production of faba bean is affected by several diseases including fungal diseases. Fusarium wilt incited by Fusarium oxysporum Schlecht. was shown to be the most common wilt disease of faba bean in Assiut Governorate. Evaluation of 16 faba bean genotypes for the resistance to Fusarium wilt was carried out under greenhouse conditions. Three molecular marker systems (inter-simple sequence repeat [ISSR], sequence related amplified polymorphism [SRAP], and simple sequence repeat [SSR]) and a biochemical marker (protein profiles) were used to study the genetic diversity and detect molecular and biochemical markers associated with Fusarium wilt resistance in the tested genotypes. The results showed that certain genotypes of faba bean were resistant to Fusarium wilt, while most of the genotypes were highly susceptible. The percentage of disease severity ranged from 32.83% in Assiut-215 to 64.17% in Misr-3. The genotypes Assiut-215, Roomy-3, Marut-2, and Giza-2 were the most resistant, and the genotypes Misr-3, Misr-1, Assiut-143, Giza-40, and Roomy-80 performed as highly susceptible. The genotypes Assiut-215 and Roomy-3 were considered as promising sources of the resistance to Fusarium wilt. SRAP markers showed higher polymorphism (82.53%) compared with SSR (76.85%), ISSR markers (62.24%), and protein profile (31.82%). Specific molecular and biochemical markers associated with Fusarium wilt resistance were identified. The dendrogram based on combined data of molecular and biochemical markers grouped the 16 faba bean genotypes into three clusters. Cluster I included resistant genotypes, cluster II comprised all moderate genotypes and cluster III contained highly susceptible genotypes.

Inheritance of faba bean resistance to Broomrape, genetic diversity and QTL mapping analysis.

Six faba bean parents and their F1 and F2 generations were used in this investigation to study the genetic system controlling resistance of faba bean (Vicia faba L.) to broomrape (Orobanche crenata). Most of the F1 hybrids were tolerant to broomrape. In the F2 generation, the population P5 × P6 (Assiut 125 × Romy 12) gave the highest value of relative yield and tolerance index. Heterosis and inbreeding depression were only positive in number of tillers/plant and seed yield/plant characters. The results indicated that the additive effect was more important than the dominance one (D > H1) only for No. of pods/plant in the F1 generation. Moreover, the narrow-sense heritability was low for most of the studied traits. Three molecular marker systems, namely RAPD, ISSR and SRAP were used for identification and estimation of the genetic diversity among the six faba bean genotypes. The three molecular markers generated DNA unique bands for all genotypes. Only, eight DNA fragments were related to Orobanche tolerance. Clearly and reproducible polymorphic markers were subjected to QTL analysis. The linkage analysis showed that, out of 34 marker loci segregated in the F2 population, 29 (85.29%) were mapped on three linkage groups. QTL analysis using SIM method performed for the 29 markers assigned to LG-1, LG-2 and LG-3 with the eight traits, number of tillers/plant, plant height, number of pods/plant, seed yield/plant, number of broomrape spikes per plant, height of broomrape spikes, relative yield and tolerance index, showing 12 putative QTLs for all traits except number of tillers/plant. From this study, it is clear that P5 × P6 (Assiut 125 × Romy12) population could be considered promising for selection for resistance to broomrape infestation.