Abstract

Kenaf (Hibiscus cannabinus L.) is a warm-season fiber crop with high biomass potential, but breeding is limited by susceptibility to root-knot nematodes and ploidy barriers that hinder hybridization with resistant tetraploid relatives such as H. acetosella and H. sabdariffa. This study evaluated induced polyploid kenaf for morphological, biomass, and stomatal traits to assess its suitability as bridge germplasm. Tetraploids were generated from diploid ‘Whitten’ and ‘H.C. 584’ using colchicine, and triploids were produced in ‘H.C. 584’ by crossing diploid and tetraploid plants. Five genotypes were propagated from cuttings and evaluated under greenhouse conditions for 60 d. Tetraploid plants were shorter than their diploid counterparts in both genotypes, with ‘Whitten’ decreasing 12% and ‘H.C. 584’ 18%. Leaf width increased in tetraploids, whereas stem diameter and leaf length were unaffected by ploidy. Stalk dry weight did not differ significantly among ploidy levels within a genotype, indicating that reduced plant height did not reduce early stalk biomass accumulation. Stomatal length and width increased markedly with ploidy, with the largest stomata observed in tetraploids. These results support induced tetraploid kenaf as promising germplasm for overcoming ploidy barriers in breeding.

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