臺灣地區栽培之「巨峯」葡萄着果量原已偏高，採行一年多收栽培方式後産量之過高更趨嚴重。爲瞭解一年多收栽培方式對果實品質及植株之影響，本試驗比較一年一收、二收與三收之果實品質，並調查果實成長期間之積算溫度及翌年新梢、花穗生長情形。
試驗結果爲夏、秋兩季果實之品質較佳，冬果品質較差。由積算溫度判別，冬果成長期間之積算溫度較夏、秋果爲少。一年一收之方式對翌年新梢及花穗生長最有利，隨結果次數之增加，翌年新梢與花穗生長情形愈差。
In order to evaluate the current method of ”Kyoho” (Vitis vinifera L.×Vitis labruscana Bailey) grapevine cultivated in Taiwan, a series of experiments on the grapevine harvest times was carried out separately in 1981 and 1982. Three treatments-one harvest, two harvests, and three harvests within a year-were conducted to determine the quality of berries, the growth of shoots and the status of inflorescence in the next year.
Results showed that the treatment of three harvests a year had the highest total yield of over 78, 000 kg/ha. But the fresh weight of individual clusters decreased with the increase of harvest times. It averaged 143 g which was only half of the cluster weight in the one-harvest-a-year treatment.
Among the fruits of all treatments, the highest heat summation of more than 1300℃ occurred in the first harvest with good quality berries. Second harvest fruits were the best in quality with a total soluble solid of over 17° Brix, a total acidity of less than 0.5 g/100 ml and a heat summation of 1227℃, but poor in the coloration of berries. The heat summation of third harvest fruits was 1062℃, which caused the total acidity of juice to higher than 0.6 g/100 ml.
The shoot growth and inflorescence of grapevine in the subsequent year varied with harvest times. The inflorescence length of three-harvests vines was 1.9 cm, which was merely half in length in comparison with one-harvest vines.
The results shown that one harvest a year is the best for grapevine cropping system. The two-harvest cropping is still applicable in Taiwan. However, the vines bearing berries for three consecutive seasons in a year have turned out to be the worst.
