Effects of Flowering Behavior and Pod Maturity Synchrony on Yield of Mungbean [Vigna Radiata (L.) Wilczek] (Report‪)‬

Introduction In mungbean [Vigna radiata (L.) Wilczek], seed yield is determined by number of produced flowers, percentage of pod set, number of seeds per pod and seed size (Mondal, 2007). In legume crops, many flowers are produced but only a few set pods are formed and result the low yield (Pigeaire et al., 1992; Fakir et al., 1998; Saitoh et al., 2004; Mondal, 2007; Islam et al., 2010). The main reason for such low yields is abscission of flowers and immature pods. If abscission could be prevented or decreased, yields of leguminous crops would be increased. The high percentage of flower abscission in legumes is due to the abscise of most later-formed flowers (Isobe et al., 1995; Kuroda et al, 1998; Mondal, 2007; Yasari et al., 2009; Islam et al., 2010). There has been much debate whether the yield of legumes is sink or source limiting, and much of the argument is in favor of the latter, as earlier-formed pods are heavier than the later-formed ones (Fakir, 1997; Kuroda et al., 1998; Begum et al., 2007). This suggests inadequate assimilate supply to later formed pods. Moreover, genotypes, which produced more flowers within a shorter time, had a greater likelihood of setting pods and retaining until maturity (Fakir, 1997; Biswas et al., 2005; Mondal, 2007). Apart from the magnitude, duration of flowering is equally important since more than seventy percent of pods plant-1 originate from the first 10-15 days of flowering in soybean (Yoshida et al., 1983; Nahar and Ikeda, 2002; Islam et al., 2010), Vicia faba (Clifford et al., 1990), pigeonpea (Fakir, 1997), and mungbean (Mondal et al., 2009). Plants that produce maximum flowers within two to three weeks after flowering also show higher pod yields in mungbean and groundnut (Mondal and Hamid, 1998; Mondal, 2007). This suggests that understanding of flowering pattern is useful in the selection of high yielding genotypes. There is however little information on flowering behaviour in mungbean. Therefore, morpho-physiological responses in flower production and flowering pattern that ultimately leads to more mature pods and final yield needs to be properly assessed. Not only lower yield but also asynchrony in pod maturity is a major problem in mungbean cultivation that is time consuming and costly practice of hand picking pods. It has been observed that only about 65% of pods can be harvested in the first picking at 70-75 days after sowing (DAS), 18% in the second at 75-80 DAS and 17% in the third at 90-95 DAS (Rahman, 1991). If we can harvest all or more than 90% of total pods in a single harvest, we will be able to lower the total harvesting cost. Thus, genotypes with synchronized maturity are desirable. The present study was conducted to study flowering pattern and its relationship with synchrony in pod maturity and seed yield in six promising mungbean genotypes along with six common cultivars.