Changes in physiological and morphological characteristics of Thai commercial guava cultivars under flooding condition

Abstract

The objective of this experiment was to study the effect of flooding on physiological and morphological characteristics of 3 commercial guava cultivars consisted “Wan Pirun”, “Pan Sritong” and “Kim Ju” cultivars. Four months old of guava trees were subjected to flooding condition for 10 weeks (10 cm. above from soil surface). Photosynthesis rate, leaf greenness and shoot length extension were collected every 2 weeks until the end of the experiment. Shoot fresh and dry weights, root fresh and dry weights, leaf number and leaf area were collected at 10 weeks after flooding. The result showed that flooding had an effect on photosynthesis rate and shoot length extension of each cultivar. “Kim Ju” cultivar showed the highest value of photosynthesis rate and shoot length extension under no flooding condition but all cultivars showed photosynthesis rate and shoot length extension decreasing under flooding. The reduction of photosynthesis rate and shoot length extension were 79.3-93.0 % and 51.1-77.0 %, respectively, when compared to control. For guava plant growth, flooding had effect to decreased shoot fresh and dry weights, root fresh and dry weights, leaf numbers, and leaf area around 49.0-75.6 % when comparing with control. While, leaf greenness was decreased only 9.2 %. “Wan Pirun” cultivar had the lowest vales of leaf greenness and shoot and root growths while, “Pan Srithong” and “Kim Ju” cultivars presented similar value of shoot and root growths. Lenticel and adventitious root formation at stem closely above and below the water level were only found in “Pan Srithong” and “Kim Ju” cultivars after 66-70 days of flooding. Base on the data, there was concluded that “Pan Srithong” and “Kim Ju” cultivars had more tolerant than “Wan Pirun” cultivar under flooding condition.