Coconut (Cocos nucifera L.) cultivation prevails in over 90 tropical countries. Dwarf coconut varieties from Asia-Pacific are prominent for their short stature, early flowering, and high yield. In Malaysia, coconut ranks as the fourth most important crop, yet production comes behind the demand due to rising industrial and household use. Improving dwarf cultivars is crucial to enhancing productivity and reducing imports. This study analyzed genotypic variability in three Malaysian recommended dwarf cultivars—Malayan Yellow Dwarf, Malayan Red Dwarf, and Pandan—to identify genotypes suitable for further development. Ninety mature palms (30 per cultivar) succeeded in their assessment for 10 phenotypic traits per palm. Such traits were nut yield (number of nuts per palm per year), palm height, girth at 20 cm and 150 cm aboveground levels, the number of female flowers, spadix length, largest unopened spathe length, the number of unopened spathes, length of 11 leaf scars, and the number of rachillas. The restricted maximum likelihood (REML) and best linear unbiased prediction (BLUP) were methods used to estimate variance components, and the multi-trait genotype-ideotype distance index (MGIDI) enabled the multi-trait selection. Significant genotypic variability was evident among coconut genotypes, with heritabilities at 69%–99% and repeatabilities at 68%–100%. Cluster and principal component analyses (PCA) distinguished the Pandan cultivar from MYD and MRD. PCA explained 83.5% of the variation (PC1: 40.8%; PC2: 18.9%), with the yield, palm height, and girth loading comprising PC1 and spathe and spadix lengths on PC2. The MGIDI identified four superior genotypes per cultivar, with yield gains up to 67% in MRD, 59% in MYD, and 34% in Pandan.
Dwarf coconut (C. nucifera L.) cultivars, inter and intra population variability, phenotypic traits, REML, BLUP, MGIDI, Cluster and PCA, yield gain
The study revealed significant genetic variability within and among three dwarf coconut (C. nucifera L.) cultivars, with the highest heritability and repeatability supporting effective selection. Yield, palm height, and girth were the main traits driving genetic variability and offering practical targets for further improvement in coconut yield.