Response to sowing dates and performance of different sunflower (Helianthus annuus) hybrids during rainy season in high-intensity cropping systems

A study was conducted for 3-years during 1995-97 on the feasibility of growing sun newer (Helianthus annuus L.) during rainy season (August-November) in the Shiwalik foothills of Punjabal at Ballowal Saunkhri. 'Jawalamukhi' sunflower hybrid was sown on varying dates, viz 4-6 August, 11-13 August, 18-20 August and 25-29 August in different years. In another trial in 1997, different hybrids, viz 'PSFH 67', GK 2002', 'SH3322', 'MSFH 8', 'PSH 17' and 'Jawalamukhi' were evaluated when sown on 8 August. The results indicated that sunflower could be grown successfully with seed yield ranging from 1559-2224 kg/ha depending on the valiable rainfall pattern in different years. The crop sown on 11-13 August gave the highest yield of seed ( 1587-2453 kg/ha) and stover (3 563-3 970 kg/ha) in all the years and there was a gradual decrease in yield with delay in sowing. The crop growth duration increased from 92-99 days but the total heal units (degrees C) decreased from 1 731-1 621 with delay in sowing, as the late-sown crop experienced lower temperature during the seed-filling period. The coefficient of variation (CV%) was low for the total growth duration (2.9%) and heat units (26%) suggesting that these parameters can be reasonably well predicted: under the present conditions. None of the other hybrids was superior to 'Jawalamukhi'. Fresh fodder yield of pearl millet [Pennisetum glaucum (L.) R. Br.. emend. Stuntz] grown uniformly before sunflower (July-August) ranged from 3 296-6 429 kg/ha in 32-55 days. The performance of winter season (November-April) crops of wheat (Triticum aestivum L. emend. Fiori & Paol.), barley (Hordeum vulgare L.), oats (Avena sativa L.), lentil (Lens culinaris Medik.) and safflower(Carthamus tinctorius L.) decreased with delay in sowing from 7 November to 3 December and depended greatly on the rainfall received during the growth season.