Determination of sowing date and plant spacing for production of green bean (phaseolus vulgaris l.) Varieties under jimma condition, southwestern ethiopia

Abstract

Green bean (Phaseolus vulgaris L.) takes the highest share among the leading vegetables exported to European and Middle East markets. Recently, it is becoming one of the most important vegetables in local markets as well. As green bean is a new introduction to Jimma area, identification of adaptable varieties with appropriate sowing date and plant spacing can provide the basis for effective green bean production. However, there is hardly any recommendation for cultivation of green beans for Jimma and similar areas. Therefore, a 5 x 4 x 2 factorial experiment arranged in Randomized Incomplete Block Design (RIBD) with three replications was conducted at Jimma, Southwestern Ethiopia from June 2010 to December 2011 with the objectives of determining appropriate sowing date, plant spacing and identifying the best candidate variety for better yield and quality of green beans (Phaseolus vulgaris L.) under Jimma condition. The treatments consisted of five different levels of plant spacing (50 cm x 7 cm, 40 cm x 15 cm, 40 cm x 10 cm, 40 cm x 7 cm, 30 cm x 15 cm), four levels of sowing date (July 3rd, July 18th, August 2nd and August 17th) and two verities (Melka-1 and Melka-5). In view of that, data were collected pertaining to growth, yield and quality of green beans and analyzed using Genstat version 11 (VSN International, 2008).The results revealed that the difference between the two varieties was highly significant (P<0.05) for all parameters studied. The variety Melka-5 gave high total and unmarketable pod yield; while Melka-1 variety gave high tenderness quality of green bean (1.780). Sowing of green beans on the 3rd and 18th of July resulted in high total pod yield (7182 kg/ha) and (7000 kg/ha) respectively; while sowing on the 3rdof July resulted in high marketable pod yield (4326 kg/ha). Total unmarketable pod yield was observed when sowing was done on the 3rd and 18th of July; while more number of seeds per pod was observed as a result of sowing on the 18th of July and 2 nd August (2.253) and (2.243), respectively. The incidence of Angular leaf spot was significantly (P<0.05) higher for July 3rd sowing; whereas high incidence of floury leaf spot was recorded from sowing on the 18th of July and high rust infestation was observed when Melak-1 sown at the 2nd of August. More snapping and tenderness quality was observed when sowing was done on the 3rd of July. Green beans spaced at 40 cm x 7 cm gave significantly high leaf area, total marketable (2531 kg/ha) and unmarketable (2609 kg/ha) pod yield; while tenderness quality was higher at 50 cm x 7 cm spacing (1.708). The interaction effects between Melka-5 and July 3 rd sowing gave high total number pod per plot; while Melka-5 sown on the 18thof July produced high value for straightness quality, and Melka-1 with July 3 rd sowing gave high fibreless quality. Green bean sown on July 3rd with a spacing of 40 cm x 15 cm gave high total number of pods per plot, while the interaction effects between 50 cm x 7 cm with sowing on July 3 rd resulted in high straightness quality. On the basis of the results of the present study, it is indicative that green beans can grow well in the study area and farmers can benefit more by practicing narrow plant spacing (40 cm x 7 cm) and earlier sowing (July 3) with variety Melka-5 to achieve high productivity and quality of green beans. However, repeating of the experiment for more seasons would help us draw sound conclusions and recommendations. Moreover, further studies are needed with regard to the improvement, nutritional quality and packages of agronomic practices for green bean cultivation.