INTRA-SPECIFIC HYBRIDIZATION IN CULTIVATED PAPAYA (CARICA PAPAYA L.) GENOTYPES
The first step at the start of a breeding programme is to establish the germplasm or collection of cultivars to provide breeders with the basic resource. After evaluation, characterization and documentation, the collection becomes the genetic inventory from which breeders can draw out accessions that can become baseline cultivars for immediate recommendation or to be used as parents for hybridization and improvement of existing commercial cultivars. Papaya is normally-seed propagated. The genetic uniformity of papaya can only be achieved either by self-pollination of hermaphrodite cultivars to achieve homozygosity in which case the cultivars are purelines or inbreds, or by hybridization of homozygous lines in which case the cultivars are heterozygous F1 hybrids. F1 hybrid papaya cultivars are better than purelines because their heterozygosity ensures better genetic buffering against environmental stress and they also exhibit heterosis in yield. Non-disclosure of inbred parents guarantees protection and exclusivity in the production of hybrid seed. Report of the pioneering papaya breeding embarked on at National Horticultural Research Institute (NIHORT); Nigeria geared towards the development and release of improved cultivars that will be accepted for commercial cultivation by Nigerian farmers is highlighted and the future breeding strategies including breeding for disease resistance, identifying the sex types at seedling stage thereby addressing requirements of industrial and pharmaceutical markets and finding new ways to conveniently serve papaya for ubiquitous consumption are also discussed.
Ibitoye, D.O., Akin-Idowu, P.E., Alo, J.A., Arile , C.O. and Iyama, T. (2011). INTRA-SPECIFIC HYBRIDIZATION IN CULTIVATED PAPAYA (CARICA PAPAYA L.) GENOTYPES. Acta Hortic. 911, 331-336
germplasm, inbred, heterosis, homozygosity, hybridization, pureline