不同時期萌芽香蕉生育及產量之研究

Studies on the Growth and Yield at Various Times of Sucker Emergence of Banana

每年三月至八高溫多雨，香蕉生長旺盛，九月至翌年二月氣候乾燥，溫度降低，香蕉生長低弱，不同時期萌芽的香蕉，所經歷的生長旺盛期與低弱期不同，形成植株生長的差異。不同時期萌芽芽香蕉片每月變化情形，大致相同，高溫多雨的夏季，每月可生長四枚以上的新葉，似是但在乾燥低溫的冬季，則每月平均僅抽展0.8枚。葉斑病為害以每年的六月至十月最嚴重，每年九月的平均枯死葉數最多。全生育期生長總葉數差異不大，平均約有25~28枚。抽穗時植株上的綠葉數，亦無顯著的差異，但以七月至九月萌芽者葉數較少。收穫時的綠葉數差異較大，九月至十二月萌芽者，平均都在4枚以上；五月至七月萌芽者，則僅有0.75~1.6枚。四月至六月萌芽者，生育期最短，從萌芽至收穫平均需16.3~16.8個月，八月至十二月萌芽者，生育期最長，從萌芽至收穫平均需19.8~20.8個月。果真成熟所需日數，亦有顯著的差異，以七月至十月者較長，從開花至收穫平均100天以上，其他各月份萌芽者，均在100天以下。果實大小品質，以九月至十二月萌芽者為優，五月至七月萌芽者較差．每株平均產量，亦以九月至十二月萌芽者最高，果房平均重量達17.29~17.92公斤，其次為一月與二月萌芽者，再次為三月、四月與八月萌芽者。產量最低為五月至七月萌芽者，每株平均果重槿有13.70~13.99公斤。每年留一月至四月萌芽的香蕉，可生產夏蕉與秋蕉；留五月至八月萌芽的香蕉，可生產秋蕉與冬蕉；留九月至十二月萌芽的香蕉，可生產春蕉與夏蕉。

Studies in detail of plant growth growing period, the development and grade of fruit as well a6 bunch yield of banana at various times of sucker emergence were conducted at the plantation of the Chiayi Agricultural Experiment Station from October, 1966 to August, 1969. Suckers emerged at different months in a year round were set up and the growth of plant height, pseudostem diameter and leaf development were measured once a month through the whole growing period. The fruit grade and yield were also recorded individually at harvesting. The results obtained are summarized as follows: (1) As the influence of seasonal variation on the growth of banana plant, there had two distinct periods: (a) from March to August when weather was warm and rainy, the growth of banana plant was very vigorous; (b) from September to the next year of February, it was a cold-dry season, thus the banana plants grew very slowly, and they showed semi-dormant status particularly on the young suckers (Fig. 1,2). Therefore, the growing curves and fluctuation of growth rates during the whole growing period of banana among the various times of sucker emergence were very significantly different (Fig. 1-4). (2) The loaf developments of banana were very closely related to the climatic condition and the outbreak of leaf spot disease. The number of new unfurling and green leaves of a plant varied with the changes meats temperature and rainfall. In warm-rainy season, more then 4 leaves unfurled every month but only 0.8 leaves unfurled monthly during the cold-dry season (Table 4 & Fig. 5). On the other hand, there was a very close relationship between the monthly number of dried leaves and infection degree of leaf spot disease. Since leaf spot took place in April but attacked seriously in June through October, thue, it was very apparent that the number of dried leaves increased accumulatively reaching a peak in September of the year (Fig. 11). (3) The total number of leaves formed by a plant at various of sucker emergence of banana were not significantly different However, it had about 25 28 leaves without counting those with leaf width of less than 15cm. before floweriug. Besides, the suckers emerged from July to September were found to have a less number of green leaves at shooting stage but without significant differences as compared with others. At harvesting time, there were more than 4 green foliages on the plant whose sucker emerged from September to December but only 0.75-1.60 green leaves were obtained on those from May to July. The differences among various times of sucker emergence were very significant (Fig. 6). (4) A very marked difference was found with growth period of banana between various times of sucker emergence. The suckers emerged from April to June had a short growth period at the average of 16.3-16.8 months, but a longest period was found on the suckers emerged from August to December that took at the mean of 19.8-20.8 months from emerging to harvesting. The differences of fruit maturing period at various times of sucker emergence were also statistically significant. Among the different times of the year, the fruits of the suckers emerged from July to October needed a longer period more than 100 days for maturing (Table 7). (5) It was evident that the suckers emerged from September to December produced vigorous plant, big finger and high quality of fruit (Table 6, 8). For the bunch weight per plant, the seekers emerged from September to December gave the highest yield with the mean of 17.29-17.92 kgs., while those from May to July showed the lowest yield at th average of only 13.70-13.99 kgs, per bunch (Fig. 9). (6) Based on the results obtained from the distribution of flowering and harvesting dates, the suckers emerged from January to April may produce for the most part of summer and fall banana, and those from May to August may yield mostly of fall and winter banana, while those from September to December may bear chiefly of spring and summer banana, respectively (Fig. 7,8). Therefore, the production of banana could be regulated by means of controlling the times of setting followers and with other plantation managements to produce banana at most favorable time with suitable quantity for exporting in the year round.