The most important crop improve¬ment are as follows:
(1) Higher yield: The main aim of crop improvement is to improve the productivity of economic productivity, e.g. vegetables, grain and fodder. Quality seeds of improved varieties are used for their commercial production.
(2) Improved quality: Quality considera tions of crop products varies from crop to crop, e.g. protein quality in pulses, baking quality in wheat, oil quality in oil seeds and preserving the quality of fruits and vegetables.
(3) Photo insensitivity and thermoin sensitivity: Most of the plants are sensitive to certain abiotic factors such as light and temperature. Development of photoinsensitive and thermosensitivity crop varieties will help in crossing the cultivation boundaries, e.g. MACS 2469 can tolerate high temperature, a HYV of wheat.
(4) Wider adaptability: If we develop those varieties of crops which have wider adaptability, then it will help in stabilising the crop production, under different environmental conditions.
For example ICPH 8 is a hybrid pigeon pea plant, which takes a short duration to mature, escapes and diseases such as Fusarium, wilt and sterility mosaic will not and yields of 30 to 40 per cent more than the popular breed is obtained. It performs well under drought, as well as high- moisture conditions.
(5) Biotic and abiotic resistance: Under different situations, crop suffers due to biotic stresses and abiotic stresses. If we develop crop varieties, which are resistant to these stresses, then we can significantly improve crop production.
For example, MUW 318’is a HYV of wheat, which is released for cultivation in nontraditional areas such as Nilgiri and Palni hills and resistant to all the rusts.
(6) Desirable agronomic traits: If we develop those varieties of crops which contain desired agronomic traits, then it will help in setting higher production. Thus, tallness, high tillering and profuse branching are desirable characters for the fodder crops. Whereas, dwarfness is desired in cereals, as dwarf varieties provide protection from lodging.
For example, breeding for resistance to red root has led to sugarcane varieties such as CO 975 and CO 62399 which increase sugarcane production in problem areas. Likewise, new varieties of chicken pea, as BG 244 and ICC 34 grow erect, have many branches and has pods from base to tip.
Some improved varieties or high yielding varieties of crop plants are as follows:
1. Rice – IR 8, Jaya.
2. Maize – Gangs 5
3. Mustard – Pusa Gold, Kranti
4. Soybean – PK 262
5. Sunflower – BSH 1
