Genetic diversity of 33 forage cactus pear accessions based on principal component analysis

The present research was undertaken to assess genetic diversity of 33 forage cactus pearaccessions introduced from different countries for their suitability in the existing fodderproduction system in Arabian Peninsula countries including Oman. These accessions wereevaluated in randomized complete block design with four replications for two consecutive years2014 and 2015 at Agriculture Research Center, Rumais in Oman. The characters cladodegreen and dry matter yields and their related traits plant height (cm), number of cladodes andcladode weight were considered for study. The results of principal component analysis (PCA)indicated that of the total four components, the first two components PC1 and PC2 accountedfor 97.65 and 2.27%, respectively which in combination contributed to 99.92% of the totalvariation among characters studied in fodder cactus pear accessions whereas remaining twocomponents PC3 (0.06%) and PC4 (0.02 %) contributed a meagre 0.08% to the total variation.The first principal component had high positive loading for only green matter yield with thehighest value of 0.993 whereas second principal component had highest loading for plantheight (0.998) in contributing to the diversity. However, PC3 and PC4 were accounted by higherpositive loading in respect of dry matter yield (0.853) and number of cladodes (0.855). Theresults of correlation analysis indicated that of 10 possible correlations from five charactersstudied, seven correlations which were found significant (p<0.05) were also positive in natureof association. The scatter of accessions based on PC1 and PC2 scores resulted in groupingthem into six clusters consisting of accession ranging from 1 to 9. These results could beapplied in either selecting higher green matter yielding accessions from high yielding groups torecommend for either general cultivation or planning and execution of future breeding programfor higher forage productivity in cactus by selecting accessions from different clusters asparents for hybridization.