ABSTRACT
Almond (Prunus dulcis [Mill.] D.A. Webb syn. P. amygdalus Batsch) is one of the most important nut crops, and its kernel is the edible part that has a high nutritional value and is used in the confectionery and cosmetics industries. The present research aimed to identify random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) molecular markers associated with important fruit traits in late-blooming almond genotypes through multiple regression analysis (MRA). The studied genotypes showed significant differences from each other in terms of the measured fruit-related traits. The ISSR primers used produced a total of 125 bands in the studied germplasm, of which 112 showed polymorphic bands. The RAPD primers produced a total of 190 DNA fragments, of which 172 fragments showed polymorphism among genotypes. Some polymorphic fragments of ISSR and RAPD showed significant correlations with the fruit traits measured. Some of these informative markers were associated with more than one trait, which could be caused by the pleiotropic effects of quantitative trait loci related to each other in different traits. For instance, some of the markers showed significant correlations with both nut weight and kernel weight, which indicates a positive correlation between these two traits. Informative markers identified in this study can be used to select suitable parents for population generation for mapping. It is also useful for selecting superior genotypes, especially when information about their genetic basis, such as a linkage map, is not available.
ABSTRACT
One of the major limiting factors in the intensive spread of apricot (Prunus armeniaca L.) in most of the countries is spring frost. Thus, the breeding efforts have concentrated on the use of late-blooming genotypes as a means of frost avoidance. The aim of the present study was to identify late-blooming genotypes with high fruit quality among seedling-originated trees. Firstly, pre-selections were done according to blooming time within 278 apricot seedling-originated trees. Secondly, the late-blooming selections were further evaluated according to their vegetative and fruit characteristics to determine superior types. Significant differences were observed among the late-blooming genotypes in terms of the traits recorded. Fruit ground color was strongly variable, including white, yellow, yellow-green, light orange, orange, and dark orange. Fruit weight ranged from 27.37 to 33.99 g, fruit flesh thickness varied from 11.16 to 13.47 mm, and total soluble solids varied between 17.00% and 23.87%. Hierarchical cluster analysis (HCA) performed with Euclidean distance and Ward's method divided the genotypes into two main clusters based on morphological traits and in some cases, the genotypes belonging to an area were clustered into different clusters. All the 48 late-blooming date genotypes selected could be useful as a parent to improve flowering season of cultivars. Also, among them, 10 genotypes were superior in terms of fruit quality-related characters, such as fruit weight, fruit color, fruit taste, and TSS, and thus they can be singled out for cultivation.
