Red Bean ( Vigna angularis ) Pioneering Trials in a Cool Mediterranean Area S.K. Yau

1. Red Bean (Vigna angularis) Pioneering Trials in a Cool Mediterranean Area S.K. Yau Fac. of Agric. & Food. Sci., American Univ. of Beirut, Beirut, Lebanon Introduction Red bean, also known as azuki or adzuki bean, is a valued pulse in East Asia. It is an annual vine widely grown in China, Korea, and Japan. Cultivars most familiar there have a uniform red color. It is commonly consumed as sweetened bean paste/cakes and porridge as a dessert.  Little work has been done to test and grow red bean in the Mediterranean countries. With a relatively high market price in the world, the author believes that it may be a profitable crop in Lebanon. If suitable cultivars and agronomic practices can be found, it may have the potential to replace illicit crops grown there.   Objectives To identify a suitable red bean line and the optimal intra-row spacing and sowing time for red bean in the high-elevation Bekaa Valley, which has a cool Mediterranean climate and is the dominant agriculture area of Lebanon. Fig. 1. Effects of intrarow spacing on seed yield and seed weight Conclusion 1. There were significant differences in seed yield and size between lines. ‘Anab-selected’, which had large seed and gave the 2nd highest yield, appeared to be the best among the lines tested in the high-elevation Bekaa Valley.  2. Intra-row spacing and sowing time affected seed yield and size differently. Intra-row spacing of 10 to 20 cm sown around the period May 26 to June 16 most probably presented the best compromise, unless seed size had a dominant effect on seed sale. Materials and Methods üIrrigated experiments were conducted in 2003 and 2005 at the Agricultural Research and Educational Center (33°56’ N, 36°05’ E, 995 m a.s.l.). üThe site has a frost-free period from mid-April to mid-November, and practically no rain falls in May to September.  üIn 2003, a strip-plot designed experiment on irrigation and intra-row spacing (5 treatments: 5, 10, 15, 20 and 25 cm) was sown on May 8. üWeekly irrigation was delivered by a sprinkler. üThe 2.5m-section closest to the sprinkler was considered as fully irrigated and the next 2.5m-section considered as sub-irrigated.  üIn 2005, there were 5 sowing dates (Apr 20, May 6, May 26, June 16, and June 30) and 7 red bean lines (Anab, L & W, Shun, Top, Asian Taste, Double Li, and Anab-selected) in the split-plot experiment. üWeekly irrigation was delivered by drip-lines. Fig. 2. Effects of sowing date on seed yield of the six red bean lines Fig. 3. Effects of sowing dates on seed yield and seed weight Results 2003 ØThere was no significant irrigation by intra-row spacing interaction on seed yield and seed weight. ØFull-irrigation gave higher seed yield than sub-irrigation (480 vs 140 kg/ha, P<0.10), but not seed weight (6.8 vs 8.8 g/100 seed). ØThe intra-row spacing of 20cm gave the highest seed yield, which was significantly higher than spacings of 5, 10, and 25 cm (Fig. 1). ØThe 10cm spacing led to the heaviest seed, which was significantly heavier than spacings of 20 and 25 cm. 2005 ØSowing-date-by-line interaction was significant for seed yield. ØFour lines gave the highest yield in the May 26 sowing (Fig. 2). ØOne line gave high yield in the May 6 and May 26 sowings, but another line gave high yield in the May 6 and June 16 sowings. ØThe highest yield (1740 kg/ha) was obtained from ‘Shun’ and ‘Anab-selected’ in the May 26 sowing. ØOn average, May 26 sowing gave the optimal yield (1180 kg/ha) (Figure 3). ØAveraged over the five sowing days, ‘Double Li’ yielded the most (1000 kg/ha) but was non-significantly different from ‘Anab-selected’ (Table 1).  ØSowing-date-by-line interaction was not significant for seed weight. ØSeed size increased with each delay in sowing and reached the highest (12.0 g/100 seed) in the last sowing on June 30 (Figure 3). ØThe highest yielding line ‘Double Li’ gave lower seed weight than the other five lines, which were non-significantly different in seed weight (Table 1).