Field evaluation of deficit irrigation effects on tomato growth performance, water-use efficiency and control of parasitic nematode infection
Two field experiments were conducted using a common tomato cultivar (GS12) to assess the effect of deficit irrigation (DI) regimes on tomato growth performance, and on root-knot nematode Meloidogyne javanica galling and abundance. Irrigation treatments consisted of five irrigation regimes: 20%, 40%, 60%, 80% and 100% of field capacity. The results showed that DI decreased significantly leaf area, relative water content, water potential, minerals content and chlorophyll content. The 80% irrigation regime caused minor reductions in plant growth, but significantly reduced nematode infection load. Nematode infection was reduced even further at higher levels of water deficit, but this also led to marked reductions in fresh and dry weights of tomato. Total tomato yield, fruit soluble solids, and acidity were decreased with increasing irrigation water deficit. Water-use efficiency was lowest in the 100% irrigation regime and highest in the 20% irrigation regime among the irrigation treatments. The results indicated that the DI at a certain limit decreased M. javanica infection without causing significant reductions in tomato growth performance.
Keywords: arid environment, crop quality, deficit irrigation, nematode, semi-arid environment, water-use efficiency, yield