Estimating spatial population structure through quantification of oil content and phenotypic diversity in Pakistani Castor Bean (Ricinus communis L.) Germplasm.

Muhammad  Arif; Haris  Khurshid; Sadar Uddin  Siddiqui; Shakeel Ahmad  Jatoi; Sohail Ahmad  Jan; M.  Ilyas; Shahid Ali  Khan; Ahson  Khan; Muhammad Ishaq  Ibrahim; Noor  Saleem; Abdul-Ghafoor

Castor bean (Ricinus communis L.) is an important non-edible oilseed crop containing 45-58% oil mainly used in pharmaceutical, petroleum, biofuels, chemicals and textile industry. We evaluated 63 castor beans accessions from Pakistani origin to determine population structure and extent of genetic divergence in local germplasm viz-a`-viz 14 agronomic traits and oil content. Higher phenotypic variability was reported for number of branches plantG1 , plant height, days to germination and days to flowering. Maximum oil content 58% was found in genotype 21102 followed by 57% in 21447, 56 24828 and 54% in 24835 and 21455. The dissimilarity coefficient matrix revealed accession pairs 24816 and 24821, 24821 and 24829, 21559 and 24821 as most diverse with highest Euclidean distances i.e. 11.45, 10.49 and 9.88, respectively. Subsequent cluster analysis distributed all genotypes into six major groups on the basis of morphological characterization. In PCA analysis, 5 of the 14 PCs had Eigen value >1, which explained 66.24% of the total variation, partitioning population into four sub-populations akin to their distinctive agro-morphological attributes. These sub-populations originated from common habitat of adjacent districts i.e., Bahawalpur, Lodhran, Multan, Muzaffargarh and D.G Khan with matching ecogeographic factors signifying availability of genetic diversity in south Punjab. We suggest utilization of Pakistani castor bean germplasm diversity, while breeding for yield components like capsule size, number and size of seed and oil content. In addition, further studies are recommended, focusing on biochemical and molecular basis of variation to fully explore local genetic diversity in the crop.