One of the major constraints to higher production of wheat on the 12 million hectares of rice-wheat grown in the Indo-Gangetic flood plains of South Asia is late planting and resultant poor plant stands. Late planting results in a linear decline in yield potential equivalent to 1-1.5% loss ha-1 d-I when planting occurs after November. Late harvest of the previous rice crop or long turnaround time from rice harvest to wheat planting are two major causes of late wheat planting. Reduced or zero-tillage options are proving effective in overcoming late planting and poor plant stands in the rice-wheat systems of Asia. This paper presents data on zero-tillage systems, ranging from surface seeding to planting with four-wheel tractor seed drills, resulting in higher yields at lower costs and savings in fuel use and tractor wear and tear. Reduced tillage systems include 'data-using' drills that combine land preparation and seeding in one operation. Both two and four-wheel tractors have been used to achieve good results. This paper concludes that conventional tillage systems can be replaced by more economic reduced tillage options. However, it is important with reduced tillage that soil moisture at seeding is maintained at a high enough level to keep soil strength low, as occurs in tilled soils. Some longer term research is needed to determine medium term positive or negative effects of reduced tillage on sustaining wheat yields.

In field trials made for two years in the dry period of a semi-arid tract under natural precipitation at the Indian Agricultural Research Institute, New Delhi, overnight seed-soaking of wheat in 0-5 % solution of 2-chloro-ethyl-trimethyl ammonium chloride (CCC) prior to sowing increased the grain yield. When treated with foliar application of the chemical in concentrations ranging between 40 and 1000 mg/1, wheat plots yielded better than did the untreated control, but no consistency was noted between the concentrations or stages of their application. The benefit from CCC was due to more root growth, increased stomatal resistance and higher leaf water potential. Treated plants extracted more water from deeper soil layers, increasing their water-use efficiency.

SUMMARYYields of pearl millet were significantly increased when grown after legume crops such as groundnut (22·6%), cowpea (24·2%) or pigeonpea (12·1%) instead of after pearl millet. A previous crop of short-duration mung did not affect the yield of pearl millet. Benefits from previous crops of groundnut and cowpea were equivalent to about 60 kg N/ha applied to a pearl millet crop following a previous crop of pearl millet.

S U M M A R YBrassica carinata (an uncultivated species) was compared with other oilseed species already under cultivation in India, on irrigated and rainfed soils. B. carinata yielded very well in a wide range of environments partly because it had a large number of primary and secondary racemes. It also showed better environmental adaptation and substantial resistance to pests and disease.Rapeseed and mustard are together the second largest oilseed crop in India. The rapeseed group includes three cultivars of Brassica campestris, namely toria, yellow sarson and brown sarson. B. campestris is a winter season (October to March) oil crop of irrigated and rainfed soils with well conserved moisture. B. tournifortii and Eruca sativa are the other oilseed crops generally grown in dryland areas with a high moisture deficit. B. juncea, commonly called mustard, is another important species widely cultivated in India, Pakistan, Bangladesh and China for its edible oil. B. napus, an amphidiploid of B. campestris and B. oleracea, is occasionally grown in northern and north-west regions of the country because of its resistance to some insects and diseases, major constraints on yield. B.carinata is an oil yielding species not yet in commercial cultivation. The present study was planned to test the potential of this species as a new oil crop in India. MATERIALS AND METHODSTwo experiments were carried out at the Indian Agricultural Research Institute, New Delhi. Experiment 1 (irrigated)This experiment was sown on irrigated sandy-loam soil on 7 October 1980 using 57 cultivars of B. campestris and one each of B. napus, B. carinata, B. juncea and Eruca sativa. All the three varietal forms of B. campestris (brown sarson, yellow sarson and toria) were included. A randomized block design (RBD) was used with three replications and 1.8 X 3 m plots. The crop was sown on ridges spaced 60 cm apart and thinned to 10 cm between plants at

SummaryField experiments conducted during the winter seasons of 1982–3 and 1983–4 in semi-arid rainfed conditions of north-west India indicated that sowing of Brassica species at the right time can considerably increase productivity. Sowing in the middle of October with daily mean temperatures around 26 °C produced 1·5 t/ha against 0·9 t/ha obtained from the crops sown 1 month later with daily mean temperatures around 20 °C. Under such conditions Brassica juncea cv. Pusa Bold (medium in stature and duration and bold seeded) gave the highest (1·66 t/ha) yield. Eruca sativa could withstand sowing at still lower temperature (19 °C). Increasing temperatures in the second fortnight of February adversely affected the productivity of a late-sown crop by reducing the reproductive phase.