Physiological interaction of soil moisture defi cit and plant population on yield and yield components relationships of maize (zea mays L.)

Maize (Zea mays L.) crops were grown at Coimbatore in the years 2009 and 2010 during the kharif season. The treatments imposed were three soil moisture levels: 100% irrigation water supply (0.8 IW/CPE ratio), 75% irrigation water supply (0.6 IW/CPE ratio) and 50% irrigation water supply (0.4 IW/CPE ratio). The plant density treatments adopted were normal spacing (60 × 20 cm), narrow spacing (30 × 30 cm) and reduced narrow spacing (45 × 20 cm) levels. Increasing the plant density, i.e., changing the plant population per unit area increased the yield of maize, even with some reduction in soil moisture levels. But further reduction in soil moisture and narrow spacing caused yield decrease. The individual treatments of normal irrigation practice, narrow plant spacing and their combinations registered better performance in terms of kernel and stover yield. From the correlation studies, the relative water content of leaves (90.7%), followed by yield components such as fi lled kernel number (67.0%) and 100-kernel weight (66.9%) were highly correlated with the kernel yield of maize.