Breeding of Fruit and Plantation Crops 2 + 1

Hybridization

 
• The mating or crossing of two plants or lines of dissimilar genotypes is known as hybridization. In plants, crossing is done by placing pollen grains from one genotype, called the male parent onto the stigma of flowers of the other genotype, referred to as the female parent. It is essential to prevent self pollination as well as chance cross-pollination in the flowers of the female parent. At the same time, it must be ensured that the pollen from the desired male parent reaches the stigma of flowers of the female parent for successful fertilization.


• The seeds as well as the progeny resulting from the hybridization are known as hybrid or F1. In Plantation crops, in coconut, intervarietal hybrids with different parental combinations such as Tall x Dwarf, Dwarf x Tall and Tall x Tall were produced in India and Srilanka. The hybrids are popular because of early bearing and high productivity. (Tall x Dwarf hybrids- Keraganga- WCT x Ganga Bondam, Kerasankara- WCT x Chougat dwarf orange, VHC 1 – ECT x Malayan green dwarf, VHC 2- ECT x Malayan Yellow dwarf). These hybrids are characterized by early bearing in 4-5 years, increased yield of nuts with a mean of 100/palm, good quality copra having high content of 176 g and oil recovery of 70%.


• Dwarf x Tall hybrids :The distinct advantage of this hybrid over T x D is that it could be produced on a large scale by regularly emasculating dwarf mother palms permitting free natural crossing with pollen from tall palms standing nearby. Use of Dwarf orange or yellow as female parent enables the identification of hybrid seedlings because of colour marker (Chandra sankara – Choughat Orange dwarf x WCT).


• Tall x Tall hybrids: It is produced by intravarietal hybridization of tall cultivars under controlled conditions. Individual palms of high breeding value are identified and these genotypes are grown on isolated seed garden and utilized for production of T x T hybrids. Though late in bearing, the yield potential of T x T hybrids is good. These hybrids are considered to be high yielding and tolerant to biotic and abiotic stress when compared to D x T hybrids.


• In cashew, to combine prolific bearing with other desirable traits with bold nut, cluster bearing habit and compact canopy, hybridization with parents selected for these characters were attempted. Hybrids performed better than the selections. Hybrid vigour could be easily be commercially utilized in cashew through soft wood grafting.