Effect of propagule length and weight on planting stock quality of bakauan-babae (Rhizophora mucronata Lamarck)

Out of the 19 seedling growth traits studied, the propagule length responded significantly on 12 growth traits. Among them are as follows: number of days to first and second leaf flushes, diameter growth, number of lateral roots, total lateral root length, lateral root dry weight, shoot dry weight, total plant dry weight, root:weight ratio, hypocotyl:weight ratio and shoot:weight ratio. On the other hand, the propagule weight showed significant reponses on nine seedling growth traits. These include number of days to second leaf flush, initial and final shoot length, initial and final diameter, lateral root dry weight, shoot dry weight, mean leaf dry weight, and total plant dry weight. Interestingly, the length and weight classes jointly demonstrated significant responses on final diameter and total plant dry weight. These responses favored both the large and heavy classes. Growth responses suggest that seedlings arising from the large and heavy classes had competitive advantages over the other remaining classes. Results presented here suggest that the competitive advantages of the large and heavy propagules over the other two length and weight classes were due to their large amount of food reserves and the manner of utilizing them. Generally, favorable results in most of the seedling growth traits were obtained from seedlings arising from the large and heavy propagule classes. Unfortunately, not all large classes showed significant responses in all of the seedling growth traits of bakauan babae. There were instances that both the medium and large classes significantly influenced the initial diameter, lateral root dry weight and hypocotyl weight ratio. Despite yielding the numerous significant responses, propagule weight to some extent is not being measured in the field. Nursery practitioners will still resort to the use of propagule length. Thus, for practical reason, it should be inferred that sorting according to propagule length should be done prior to sowing. A timely sowing operation could be adopted in cases where propagule of varied length are to be collected. But, for best results of bakauan-babae planting stocks, propagules weighing 114.80-145.99 g and with lengths ranging from 69.86-83.19 cm are highly preferred