Effects and Use of Heterosis in Plant Breeding
Manifestation (Effects) of Heterosis:
1) Increase Yield:
Heterosis is generally expressed as an increase in the yield of hybrid and may be measured in terms of grain, fruit, seed, leaf, tubers, etc.
2) Increased Reproductive Ability:
Hybrids exhibiting heterosis show an increase in fertility or reproductive ability.
3) Increase in Size and General Vigour:
The hybrids are generally more vigour, healthier and faster growing.
4) Better Quality:
In many cases, hybrid show improved quality. Ex. In Onion keeping quality.
5) Earlier Flowering and Maturity:
Hybrids are earlier in flowering and maturity than the parents. Ex. Tomato.
6) Greater Resistant to Disease and Pests:
Hybrid exhibits a greater resistance to insect of disease than parents.
7) Greater Adaptability:
Hybrids are more adopted to environmental changes than inbreds.
8) Faster Growth Rate:
Hybrids shows faster growth rate than their parents but the total size may be comparable to that of the parent.
9) Increase in Number of Plant Parts:
In some cases, there is an increase in the number of nodes, leaves and other plants parts, but the total plant size may not be larger.
Use of Heterosis in Plant Breeding:
Heterosis is exploited through the development of hybrid. It is commercially exploited in seed production of cross pollinated crops like Jawar, maize, bajara, onion, and cucurbit. It has been also used in some self- pollinated species such as Rice, wheat, tomato, and brinjal, etc.