A hybrid for Himalayan hills and peninsular region

Maize occupies 146.7 m ha globally with a production of 699.3 m tones. The area under maize in India was 7.89 m ha in 2006-07 with a production of 15.097 m tones. It is also an important cereal of North-Western Himalayan region of India and occupies 0.65 m ha with an average productivity of 1,728.7 kg/ha (Fertilizer Statistics, 2007-08). The remarkable growth of demand of maize in Asia goes beyond simple demographics to fundamental changes in diet and per capita income. More than 50% of the maize grown in Asia is used for livestock feed, primarily due to strong economic growth and rapid urbanization experienced by many of the continent's nations. In India, of the total maize grain produce, 35% is currently used for food; about 25% for livestock feed, 25% for poultry feed, 2% for starch and 1% for seed. It is expected that the demand for Livestock and poultry feed will increase in future.

Since Independence, the average productivity of maize in the country has increased from 547 kg/ha to the present level of 1,938 kg/ha and hybrids have played a key role in enhancing production and productivity at the national level. Productivity of kharif maize has been recorded much lower than that of spring and rabi crops and there is tremendous scope to increase the yield of the kharif maize. In fact, maize is grown throughout the country under different elevations. Based on agro-climatic conditions, it is grouped into five zones, viz. Zone I (J&K, HP, UK, and NEH region); Zone II (Delhi, Punjab, Haryana, West UP); Zone III (East UP, Bihar, Jharkhand, Orissa, Chhattisgarh, West Bengal); Zone IV (Maharashtra, Andhra Pradesh, Tamil Nadu); and Zone V (Gujarat, Rajasthan, Madhya Pradesh). It has been recorded that 15-20% increase in yield could be achieved by the use of seed of high yielding varieties coupled with improved agronomic practices and plant protection measures.

Normal maize protein has a biological value which is 40% of milk. Hence, the remaining protein needs to be supplemented from legumes and animal products. The essential amino acids like lysine, tryptophan and threonine are in reduced quantities in normal maize, lysine being the most limiting amino acid followed by tryptophan. In this context, 'Quality Protein Maize' (QPM) assumes great significance. QPM looks and tastes similar to normal maize. However, the protein profile of QPM maize is much better and it is 90% of the milk protein. This change is because of change in the protein profile of the endosperm of the maize kernel. India has released many QPM hybrids, all of which are full season maturity; therefore they are not suitable for hills and peninsular India where short duration maize cultivar fits well in the cropping system. VPKAS has developed a short duration QPM maize hybrid, namely 'Vivek QPM 9' which was released for the Zone I and Zone IV of India in 2008. The details of this hybrid are presented below:

Characteristics of Vivek QPM 9'

'Vivek QPM 9' is QPM version of the most successful single cross hybrid ' Vivek Maize Hybrid 9' developed through conversion of its parental lines through 'marker assisted selection' strategy complementary to conventional hybrid breeding method. 'Vivek QPM 9' possess 0.83% tryptophan as compared to 0.59% in 'Vivek Maize Hybrid 9', i.e. 40.7% increase in tryptophan (%), 28.9% increase in lysine, 23.3% increase in Fe and 16.0% increase in Zn over that in 'Vivek Maize Hybrid 9'.

'Vivek QPM 9' is an extra-early, single cross hybrid of VQL 1 x VQL 2. It exhibited a wider adaptability and consistently performed well across the zones. It has been released by Central Sub-Committee on Crop Standards, Notification and Release of Variety in 2008 for Zone-I and Zone-IV in which 3.2 million hectare area is occupied by maize. An average yield performance of 'Vivek QPM 9' was 58.43 q/ha in Zone-I and Zone-IV, respectively, which was at par with 'Vivek Maize Hybrid 9' in Zone I (59.31 q/ha) and Zone IV (54.04 q/ha). 'Vivek QPM 9' responded to higher doses of nitrogen (N=160 kg/ha) in both the year of evaluation.

The grains of 'Vivek QPM 9' are yellow, semi-flint, flat and medium-bold with average 1,000 grain weight of 310g. It matures in 85-90 days in hills and 80-85 days in plains. Plant of 'Vivek QPM 9' is sturdy 190-200 cm tall in hills and 165-175 cm in plains. Ear placement is medium-broad leaf green. Days to 50% pollen shed and silk in Zone-I and Zone-IV varies between 47.5-49.9 days and 48.1-52.4 days, respectively. Tassels are large and open, glume is purplish green, anther is light purple and silk is purple in colour. Ear is cylindrical and long with white cob wood.

Seed production

Parental lines, viz. VQL 1 (female) and VQL 2 (male) nick well and have excellent pollen production ability. VQL 1 and VQL 2 should be grown in 2:1 and even 3:1 ratio for economic seed production. An isolation distance of 300-400 m should be maintained to prevent any other pollen source. The female rows (VQL 1) should be de-tasseled before pollen dehiscence. The male parent, VQL 2 is a heavy pollen shedder which results in nearly 14-15 q/ha hybrid seed ('Vivek QPM 9') under optimum conditions. The hybrid maize seed production is mainly taken during rabi season in southern India. The perfect nicking of male and female parents during rabi season at Hyderabad, makes it suitable for economic seed production and profitability.

Sowing method, planting geometry and seed rate

Field should be prepared by two-three ploughing. Seed should be placed in furrows at 5 cm depth behind the plough. For proper spacing, line to line and plant to plant distance should be maintained 60 cm and 25, respectively. The recommended seed rate is 20-22 kg/ha for higher production.

Compost - fertilizer application and weed control

After field preparation, 10 tonnes/ ha FYM should be mixed in the soil at least 15 days before sowing. For extra-early hybrids 100-120 kg of nitrogen, along with 60 kg of phosphorus and 40 kg of potash per hectare is recommended however, the precise level of application of phosphorus and potash should be modified on the basis of soil test. Total quantity of phosphorus and potash along with one-third dose of nitrogen should be applied in the furrows before sowing while the remaining quantity of nitrogen should be applied as top-dressing at the knee-height stage (25-30 DAS) and at tassel stage, in two equal splits. During initial stages, the growth of maize plant is suppressed by weeds. For better weed management in the crop, pre-emergence application of alachlor @ 2.0 kg a.i./ha, followed by two hand weeding at 15-20 days and 30-35 days after sowing of crop should be done. After weeding, the crop should be earthed-up for better plant should and proper drainage of water.

Disease management

Turcicum leaf blight is an important disease of maize in these zones. 'Vivek QPM 9' possesses high degree of tolerance to turcicum leaf blight. However, turcicum leaf blight caused by Exerohilum turcicum appears as slightly oval, water soaked small spots on the leaves. These small spots grow into elongated, spindle-shaped necrotic lesions. 'Vivek QPM 9' exhibited moderate degree of resistance and tolerance to maydis leaf blight and turicicum leaf blight, respectively, in both artificial and natural conditions. Under artificial epiphytotic conditions reaction of 'Vivek QPM 9' showed tolerance (Zone I: 2.7; Zone IV: 4.3) to turicicum leaf blight and is superior to the national checks, viz. 'Surya' (Zone I: 4.0: Zone IV: 5.0), 'Amar' (Zone I: 4.0; Zone IV: 4.5), 'HIM 129' (Zone I : 3.8; Zone IV: 3.0) and even the latest check 'Vivek Maize Hybrid 17' (Zone I: 2.8; Zone IV: 4.5). Seed treated with Thirum 2.5 g/kg of seed before sowing reduces the incidence of disease. If disease appears, two to three sprays of Mancozeb 0.25% at a weekly interval control the disease.

Harvesting and threshing

Maize crop grown for grain are harvested after drying of the husk when the grains are nearly dry. Cobs should be removed from the standing crop and then dehusked. Harvested ears are sun-dried before shelling. For removing the grains from the cobs, maize sheller can be used for increasing the labour efficiency. Both power- and hand-operated low priced maize shellers are available in the country. Maize thresher will be better option for comparatively large acreage in comparison to the traditional methods. Before storage, grains should be properly dried, because at high moisture level (above 10-12%) chances of insect-pest damage to the stored grains increases. Farmers should not save their own seed from the hybrid plots for the next season, as the advance generation hybrid seeds lead to yield reduction to the level of 25-30%.

Farmers' preference

Farmers prefer this hybrid over the existing varieties owing to its extra-early maturity of 85-90 days in hills and 80-85 days in plains, economic seed production, better seed yield potential, higher number of cobs per plant, better green fodder yield and moderate degree of tolerance to diseases and insect-pests. In view of its better nutritional quality due to the presence of higher tryptophan and high lysine it will be of an advantage for hilly areas. Moreover, besides being suitable for rainfed conditions, this variety will be suitable for intensive cropping in irrigated conditions.

A large section of the population in the Indian sub-continent, Africa and Latin America depend on maize as a staple food. Development and dissemination of suitable QPM composites and hybrids for different imparting food and nutritional security to the underprivileged population. QPM is grown over 9.0 million hectares of area in the world; however, the area under QPM maize in India is negligible. Therefore, cultivation of QPM maize in the tribal and under-privileged parts of India should be taken on a priority to fight against protein-malnutrition.

SUMMARY

'Vivek QPM 9' is QPM version of the most successful single cross hybrid 'Vivek Maize Hybrid 9' developed through conversion of its parental lines through 'marker assisted selection' strategy complementary to conventional hybrid breeding method. The grains of 'Vivek QPM 9' are yellow, semi-flint, flat and medium-bold with average 1,000 grain weight of 310 g. It matures in 85-90 days in hills and 80-85 days in plains. An average yield performance of 'Vivek QPM P' was 58.43 q/ha and 54.35 q/ha in zone I and zone IV, respectively.