Pods and seeds characteristics within a pod crop of an amaltas tree (Cassia fistula L. - Caesalpiniaceae): I. Insect infestation, number of seeds per pod and the packaging cost

The total pod crop of 166 pods was collected from a solitary tree of Cassia fistula L. Excluding unripe pods, 101 mature fruits were air-dried for around 100 days in laboratory and studied for their insect infestation, size dimension, seed content, pod shape deformation, seed weight variation and seed packaging cost. Besides a leaf-stitcher (Piesmopoda obliquifasciata Hamps), two more insects associated with the pod - a seed borer moth, Trachylepidia fructicasseilla Ragonot and Oxyrhachis rufescens. ). The mean number of infestation (number of cocoons of T. fructicasseilla per pod) was 0.5743 plus minus 0.1804 - maximally reaching to 12 in one pod only. The distribution of cocoons amongst pods was highly positively skewed. The C. fistula pods were slightly lesser than 40 cm in length on an average - ranging from 16.6 to 51.0 cm and around 1.08 to 2.20 cm in diameter (mean = 1.80 plus minus 0.18). The pod weighed from 12.7 to 91.0 g in mass and 23.7 to 189.9 cm3 in volume (mean = 100.5 plus minus 3.5 cm3). The part of pod admeasuring less than or equal to 1cm in diameter was devoid of any seeds or contained highly shriveled seeds. The number of locules in pods distributed asymmetrically (negatively skewed) and averaged to 93.92 plus minus 2.73 - varying from 38 to 127 per pod. The yield of healthy seeds fluctuated greatly from none to 110 seeds / pod averaging around 55.78 plus minus 2.29 seeds. The number of shriveled seeds per pod averaged to 4.41 plus minus 0.6845 per pod and exhibited highly positively skewed distribution with long tail with maximum number of shriveled seeds from a pod to be 49. There was a great degree of multi-colinearity among the structural and reproductive parameters. The distribution of seed weight of 100 randomly-selected and individually-weighed seeds was leptokurtic and negatively skewed. The seed weight of individual seed averaged to 109.5 plus minus 3.10 mg and varied around 28.2% i.e., around 3.23-folds. Clearly, the mean seed weight was a direct function of the pod weight but varied negatively with the total number of seeds developing in a pod. The data indicated a degree of trade-off between seed weight and seed number. The packaging cost calculated in terms of residual pericarp biomass (g) per g seeds in healthy pods averaged to 6.9613 plus minus 0.4609 g and varied with the pods from 3.69 to 14.16g per g seeds (3.84-folds variation).