Efficacy of auxin foliar application on the growth and yield of green Romaine (Lactuca sativa L. var. Jericho) grown under nutrient film technique (NFT) hydroponic system

Abstract

Green Romaine (Lactuca sativa L. var. Jericho) is one of Malaysia's trendiest salad greens. It provides many nutrients which vital for human health and body maintenance. This phenomenon has led to an increased in green Romaine production in Malaysia. However, there are several limitations to cultivate this vegetable since conventional planting techniques are still practiced in Malaysia. The present study was undertaken to investigate the efficacy of auxin foliar application on the growth performance and yield of green Romaine grown under the nutrient film technique hydroponic system. The green Romaine was treated with three different application rates of auxin (Indole-3-Acetic Acid); T0, control (0.0 ppm), T1 (50.0 ppm), T2 (100.0 ppm) and T3 (150.0 ppm). The mean value of growth and yield of green Romaine were significantly increased at a lower concentration of auxin application (T1). At this lower application rate, the leaves number of green Romaine significantly increased (P≤0.05) with mean value ranging from 17.0 to 22.0 leaves per plant as compared to the T0, T2 and T3. However, all treated plants do not show any significant increase in term of chlorophyll content. The yields of green Romaine (fresh weight and dry weight) exhibit similar pattern where the auxin foliar application at T1 significantly increased the mean value of the yield parameters with 113.0 - 130.0 g of plant fresh weight while 7.0-10.0 g of plant dry weight as compared to the highest concentration of T3, respectively. This result suggested that a low concentration of auxin helps to increase the growth performance and yield of green Romaine, thus highlights its potential as an effective plant growth promoter for plant grown under hydroponic system.