Comparison of Phenological, Morphological and Pomological Characteristics of Six Apricot Promising Genotypes in Khorasan Razavi Province

Iran is the fourth largest apricot producer in the world. It is important to know the level of genetic diversity in breeding programs. Local genotypes are important because they are environmentally friendly and have beneficial genes in breeding programs. Therefore, this study was conducted with the main purpose to investigate the characteristics of phenology, morphology and pomology of six promising apricot genotypes in order to determine the best genotypes in Khorasan Razavi Province condition.

This study was conducted to evaluate characteristics of  six selected genotypes (‘190’, ‘269’, ‘414’, ‘464’, ‘390’ and ‘177’) compared to ‘Ordubad-90’ (as a control) with the aim of assessing their compatibility in Khorasan Razavi climatic conditions in a randomized complete block design with three replications, at Golmakan Research Station during the 2017-2019. These genotypes were selected randomly from the Azerbaijan apricot populations around 15 years ago and were undergoing preliminary studies in the main habitat and collecting and experimental orchards. During the research period, all genotypes were completely uniform in terms of environmental conditions and garden management. Quantitative analysis of variance was performed using SPSS software and comparison of means using Duncan's multiple range test at a probability level of 1%.

Results showed that significant differences between genotypes in terms of flowering dates and fruit ripening. So that, Genotypes of ‘269’ were the earliest (19 March) and ‘190’ were the most late flowering (27 March) and, in the terms of fruit ripening time, genotype of ‘177’ were the earliest (third decade of May) and genotype of ‘190’ were the most late (second decade of July). Also, genotype of ‘414’ had the highest height (302.57 cm), crown width (278.03 cm), trunk cross section (42.75 cm2), annual vegetative growth (58.98 cm) and size index (8.76 m). These results are consistent with the findings of Nejatian and Arzani (2002) and Mesbahi et al. (2014) on a relatively significant diversity in the morphological characteristics of the studied genotypes. There was direct correlation between fruit size and stone size, so that, the highest fruit weight (65 g), stone weight (3.49 g) and kernel weight (1.93 g) was in genotype of ‘414’. This result is agreement with Asma and Ozturk (2005) who reported that there are direct correlation among fruit weight, stone weight and kernel weight in the studied apricot genotypes in Turkey. The highest acidity content (0.67%) belonged to genotype of ‘177’, the highest pH (4.97) was in genotype of ‘390’ and the highest yield (20.66 kg) was in genotype of ‘190’. The obtained results are consistent with the results of Rahnemoon et al. (2005) on the existence of a significant difference between the mean percentage of sugar and the content of total organic acids. Accordingly, with the increase of soluble solids during fruit ripening, the amount of total acid decreased, which is consistent with the results of Asma and Ozturk (2005). Also, there was a significant negative correlation between flowering time and yield at the level of 1% (-0.704). These results are consistent with the findings of Piir et al. (2017).The results of principal component analysis showed that PC1 factor with 47.06% of the total changes indicates fruit weight, stone weight and core weight, which can be called the factor of pomological traits. PC2 factor with 19.63% of the total changes indicates height, crown width and trunk cross section, which can be called the factor of morphological traits. PC3 factor with 15.14% of the total changes indicates the chemical properties of the fruit. The PC4 factor with 7.62% of the total changes indicates the time of beginning of flowering, the number of days from the full blooming stage to fruit ripening and yield, which can be called the factor of phenological traits. These four combinations accounted for about 89.45% of the total variation, and the other variations included a slight variation. These results are comparable to the results of Janatizadeh et al. (2011) regarding cultivars in Shahroud city.

Genotype of ‘177’ is recommended because of its early ripening. Also, genotype of ‘144’ due to large fruit size, genotype of ‘190’ due to late ripening and high yield compared to ‘Ordubad-90’ (control) are recommended.