Adaptation of lentil (<i>Lens culinaris</i> Medik.) to Mediterranean-type environments: effect of time of sowing on growth, yield, and water use

This study examined the adaptation of lentil ( Lens culinaris Medik. cv. Digger) to dryland Mediterranean-type environments of southern Australia and determined the effect of time of sowing on growth, yield, and water use. Phenology, canopy development, radiation absorption, dry matter production and partitioning, seed yield, and water use were measured from a range of sowing times at a number of field locations in south-western Australia in 1994, 1995, and 1996. Contrary to previous results with poorly adapted cultivars, our study showed that lentil is well adapted to low to medium rainfall regions (300-500 mm/year) of south-western Australia and that seed yields greater than 1·0 t/ha and up to 2·5 t/ha can be achieved when sown early. Even in the dry season of 1994 when May-October rainfall was &amp;lt;200 mm, yields of approximately 1·0 t/ha were produced from early sowings. Seed yields were reduced with delayed sowing at rates of 4-29 kg/ha · day. Sowing in late April or early May allowed a longer period for vegetative and reproductive growth, rapid canopy development, greater absorption of photosynthetically active radiation, more water use, and, hence, greater dry matter production, seed yield, and water use efficiency than when sowing was delayed. Early-sown lentils began flowering and filling seeds earlier in the growing season, at a time when vapour pressure deficits and air temperatures were lower, and used more water in the post-flowering period when compared to those treatments where sowing was delayed. The values of water use efficiency for dry matter and grain production, and transpiration efficiency, for early-sown lentil (up to 30 kg/ha · mm, 11 kg/ha · mm, and 20 kg/ha · mm, respectively) were comparable to those reported for cereal and other grain legume crops in similar environments. The development of earlier flowering cultivars than Digger with greater dry matter production together with improved agronomic packages will increase and stabilise lentil yields in low rainfall environments of southern Australia.