Water use characteristics of selected South African maize (Zea mays L.) landraces compared with commercial hybrids.

Abstract

In South Africa, maize is the staple food, especially in rural areas. The majority of people in these areas rely on rain-fed farming for their agricultural production. Traditional maize landraces are still a feature of the agricultural landscape in rural areas thereby indicating their importance. However, climate change poses a threat to the availability of water, particularly in sub-Saharan Africa where drought is deemed to be prevalent. The aim of the study was, therefore, to compare the water use characteristics of two maize landrace varieties, GQ1 and GQ2 (originating from Gqunge location, Centane Eastern Cape, South Africa) with two popular high yielding commercial hybrids (SC701 and PAN53). Initially, seed quality testing was determined using the standard germination, electrical conductivity and tetrazolium tests. A controlled environment study was then conducted in which the landraces were compared to hybrids across three water regimes [30% crop water requirement (ETc); 50% ETc and 80%ETc]. Separate field studies were conducted to evaluate the growth, development, yield and yield components of these varieties under varying environmental conditions – Ukulinga (irrigated and rain-red) and Swayimani (rain-fed). Results of seed quality tests showed that landrace GQ2 had comparable seed quality to hybrids. However, overall, hybrids had superior seed quality to landraces. Results from the controlled experiment also showed that emergence of landrace GQ2 was at par with hybrids. Subjecting both landraces and hybrids to water stress (50% ETc and 30% ETc) resulted in shorter plants compared to non–stressed plants (80% ETc). Plants also tasselled earlier in response to water stress. The landrace GQ2 continued to perform similarly to hybrid varieties under water stress conditions. In field trials, the dominance of hybrids, attributed to hybrid vigour, was more pronounced under optimum conditions than sub-optimum conditions. Under a low input system (Swayimani), landraces performed at par with hybrids. It can therefore be concluded that landraces of good seed quality may be suitable for cultivation under sub-optimum low input systems where their ability to adapt enables them to produce stable yields and still provide a valuable germplasm resource.