Response to planting date, stress tolerance and genetic diversity analysis among okra (Abelmoschus esculentus (L.) Moench.) varieties

Abstract

Six okra [Abelmoschus esculentus (L.) Moench.] varieties were studied for the growth and yield at two different planting dates in 2016 and 2017 in the Research Farm of Department of vegetable crops, Faculty of Agriculture, Assiut University, Egypt. The experiments were carried out in a split-plot design. The results revealed that the measured growth, yield attributes and yield parameters (days to flowering, plant height, no. of branches/plant, no. of fresh pods/plant, weight of fresh pods/plant, length of fresh pods and total yield of fresh pods) of the studied varieties were significantly affected by planting dates. The early planting date ‘15th of March’ enhanced growth and yield parameters of the okra variety ‘Pusa Sawani’. The varieties ‘Iraqi’ and ‘Hala’ were less adapted to Upper Egypt weather. The okra variety ‘Pusa Sawani’ showed the highest performance under Assiut weather and was suggested to cultivate at summer season in Upper Egypt. The six okra varieties were grouped into four clusters based on agro-morphological traits. Among these varieties, ‘Pusa Sawani’ variety was separated only in a cluster which had the highest mean values for most of agro-morphological traits. The six varieties were screened for drought, salinity and heat stress at early growth seedling. Significant variation was observed among the varieties. These varieties were grouped into two main clusters based on tolerance indices. Three molecular marker techniques, ISSR, SRAP and SSR were used to study the genetic diversity among the six varieties and to detect markers related to agro-morphological traits and drought, salinity and heat stress tolerance. These results revealed at least one marker related to agro-morphological traits and/or drought, salinity and heat tolerance.