Eftal Düzyaman

Phenotypic Diversity within a Collection of Distinct Okra (Abelmoschus esculentus) Cultivars Derived from Turkish Land Races

Ten traditional, Turkish okra cultivars (Batı Trakya, Akköy 41, Kabaklı II, Denizli, Denizli uzun, Bornova (TR-57377 and TR-57420), Amasya Çiçek, Balıkesir T-1, Ağlasun/Burdur) and one commercial cultivar (Sultani/May Seed Company) were selected to represent the variability within domestic okra germplasm from the Anatolian Plateau. Replicated field trials were conducted to evaluate a total of 21 morphological, horticultural and physiological characteristics. Principal component (PC) analysis revealed that first two PC axes explained 49.66% of the total multivariate variation with the first six PC axes explaining 84.23%. The first PC axis separated number of locules, mature pod length and internode length, while the second PC axis separated pod yield/plant, pod number/plant, pedicel length and number of branches. All 21 characters were statistically significant among the cultivars and had at least one high coefficient in at least one of the first six PC axes, which demonstrated that all of them served as distinguishing characters among the cultivars. By using the unweighted pair-group method with arithmetic average four main clusters were consistently formed across all years. The four clusters were also related to the eco-geographic distribution of the cultivars. Each cluster members were also described for their main characteristics, which also provide useful criteria for further evaluation of okra germplasm across Turkey.

Cultivar differences in yield distribution patterns in okra [Abelmoschus esculentus (L.) Moench]

A total of 15 okra cultivars of Indian, Turkish, West African, and United States origin with diverse plant traits were selected to investigate the distribution patterns of yield throughout the harvest period. The proportion of fruits harvested up to mid-harvest period (FMH) was calculated for each cultivar and taken as a criterion in transforming yield distribution patterns into numerical variables. Cultivars showed a gradation for FMH values ranging from 64.5% to 30.7%. High FMH values were exclusively found in the Indian cultivars, whilst there was no origin-specificity for lower FMH values. Most parts of the plant architecture were associated with FMH. When moving from lower to higher FMH values, the number of lateral branches and consequently the proportion of yield carried by the lateral branches decreased (both at P < 0.001) and flowering initiated earlier (P < 0.001). However, plants showed reduced mean stem diameter (P < 0.05), leaf area (P < 0.001), and fruit weight (P < 0.05). Hence, fewer generative nodes per plant were formed (P < 0.001). However, the proportion of generative nodes translated into fruits was higher (P < 0.001), and consequently a greater number of fruits per plant was harvested (P < 0.01). Coefficient of determination (R 2) analysis revealed that a multiple regression model containing the 3 traits most correlated with FMH [number of days to flowering (r = –0.89), first flowering node (r = –0.84), proportion of generative nodes translated into fruits (r = 0.80)] explained 85% of the variation in FMH. Number of days to flowering alone explained 79% and a complex regression model containing all variables (10 variables) explained 90%. Traits associated with yield distribution patterns may be considered in introducing cultivars to different ecological and production systems, as well as in selection for breeding lines.

Type of Plant Architecture Can Conceal Fruit During Harvest of Okra

Abstract Fruit concealed by several plant parts are often overlooked during harvest in okra (Abelmoschus esculentus(L.) Moench), causing significant reductions in marketable yield. Effects of plant traits contributing to marketable fruit being missed during harvest were tested in 15 okra cultivars having different plant architectures. Significant correlations between the percentage of overlooked fruit (POF) and several traits were found. There were significant correlations between POF and leaf area, numbers of lateral branches, plant height, number of nodes/ plant and internode length. Correlations between POF and plant height and internode length were negative. Fruit diameter, length, and weight; fruit weight/plant and fruit number/plant; petiole length; and stem diameter were not related to POF. The calculated bias and the coefficient of determination revealed that leaf area accounted for 62% of the variability observed for POF among cultivars; while internode length accounted for only 9% of variability. These plant traits should be considered in evaluation of cultivars for commercial production and in developing of breeding lines in okra.