Cultural Practices Affecting the Growth and Tuber Yield of Yam Bean (Pachyrhizus erosus L.)

얌빈 생육과 괴경 수량에 영향을 미치는 재배요인

Abstract

This study was conducted to establish a domestic cultivation system of a newly introduced yam bean (Pachyrhizus erosus L.). Growth and yield were investigated in response to various cultural practices, such as seedling raising, planting distance, pinching, and flower pruning. Optimum conditions for raising of seedling were an average temperature of $22^{\circ}C$ for 30 days. Considering of the raising efficiency and the convenience of transplanting, 128 cells per tray was a suitable size. When pinching at a height of 120 cm from late July to early August, yield increased by 22% compared to no pinching. Flower pruning between late August and early September increased the number of tubers and tuber yield by 32% in comparison with no flower pruning. Yam bean seedlings planted at $50cm{\times}30cm$ spacing resulted in 30% yield increase as compared to wider spacing of $100cm{\times}30cm$. Our results thus suggested that the optimal combination of cultural practices ($50{\times}30cm$ planting distance, pinching at 120 cm height, and one time of flower pruning) increase profitability by 107%. All these results suggest high possibility of yam bean as a new income crop in Korea.

새롭게 도입된 얌빈의 국내 재배기술 확립을 위하여 육묘조건, 적심, 적화, 재식밀도 등의 재배요인에 의한 생장과 수량반응을 조사한 결과는 다음과 같다. 얌빈은 P.E. 하우스내에 전열 온상을 설치하여 평균 $22^{\circ}C$로 유지하여 30일(적산온도 $650^{\circ}C$) 육묘하면 건전묘 생산이 가능하였다. 트레이 규격에 따른 출현 특성의 차이는 없으며, 셀 크기가 클수록 묘 생장량이 증가하지만 육묘효율, 이식작업의 편의성을 고려하여 128공 트레이가 적합하였다. 7월 하순에서 8월 상순에 120 cm 높이에서 적심을 하면 수량이 23% 가량 많아지며 8월 하순에서 9월 상순 사이에 적화를 하면 괴경수와 괴경중이 증가하여 수량이 32% 가량 많아진다. $50cm{\times}30cm$로 정식하였을 때 관행 $100cm{\times}30cm$보다 수량이 30% 증가하였다. 적심, 적화, 재식밀도 최적조합처리는 무처리에 비해 경제적으로 107%의 이익적인 요소가 발생하였다. 이상의 연구 결과 얌빈의 최적 재배기술 적용을 통해 국내에서 새로운 소득 작목으로서 유망할 것으로 판단된다.

Fig. 1. Meteorological data in Andong, Korea during 2014-2016.

Fig. 2. Growth stage and accumulated temperature for yam bean (Pachyrhizus erosus L.) cultivation in Andong, Korea. Bars in graph mean standard deviations (n=3).

Fig. 3. Seedling characteristics and tuber yield of yam bean (Pachyrhizus erosus L.) as affected by raising condition. A, C, E, and G are respectively days to emergence, dry weight, relative growth rate, and tuber yield by tray cell size. B, D, F, and H are those affected by raising temperature and periods. ^zMean separation within each graph by Duncan’s multiple range test at P=0.05.

Table 1. Temperature conditions for raising seedlings of yam bean (Pachyrhizus erosus L.)

Table 2. Growth and yield of yam bean (Pachyrhizus erosus L.) influenced by pinching height

Table 3. Growth and yield of yam bean (Pachyrhizus erosus L.) influenced by flower pruning

Table 4. Growth and yield of yam bean (Pachyrhizus erosus L.) influenced by planting space

Table 5. Comparison of growth and yield of yam bean (Pachyrhizus erosus L.) cultivated under two different cultural practices

Table 6. Economic analysis of yam bean (Pachyrhizus erosus L.) cultivated under two different cultural practices