Recommendations on choosing your best dry bean cultivar are based on the results of the National Dry Bean Cultivar trial using three seasons’ data (2003/04 to 2005/06). Factors that determine adaptation Rust is common in KZN and Mpumalanga, especially on late plantings, so plant early and/or apply effective chemical control. I n Table 4 the effect of fungicides on the yield of various cultivars on sprayed and unsprayed trials is compared for three seasons at Cedara and Greytown (the last only at Cedara). The percentages indicate the largest yield increase that a producer can expect because of the control of fungal diseases. In the case of rust-resistant cultivars, the control of ascochyta and angular leaf spot (ALS) contribute to a yield increase. Because the results for some cultivars varied greatly between seasons, these figures should be taken as indications of what could happen if conditions are favourable for the development of fungal diseases.
The effect of fungicides will be less striking in areas further west. A ll small-seeded cultivars are resistant to ALS. Most large-seeded cultivars are susceptible, but seven with resistance were included in the past season’s trials (PAN 116, Sederberg, PAN 9249, PAN 118, PAN 139, PAN 9257 and OPS-RS4). Bacterial diseases, especially halo blight and bacterial brown spot, are more common west of the Drakensberg than in KZN. C ultivars with short growing seasons and determinate growth habits generally have lower yield potential (especially in areas with cool nights), than those with a long growing season and which are better adapted to higher night temperatures. D ecide on a cultivar that fits into the available growing season. Seven days can generally be deducted from the length of the growing season indicated in Table 4 as the beans are already physiologically mature and will not be harmed by frost. High or low temperatures will shorten or lengthen the growing season so the figures in Table 4 must not be regarded as absolute. Under hot, dry conditions before harvest time, beans will ripen on average 10 days earlier than normal; under cool, wet conditions, beans ripen 10 to 20 days later than normal. Avoid planting large areas with cultivars that are inclined to shatter. Harvest such cultivars as soon as possible after ripening. Small white canning beans There is a good market for canning beans.
Only cultivars that are acceptable to canners should be planted, as the market for pre-packed small white beans is limited. Teebus (susceptible to rust) has the best canning quality and reaches the highest price for choice grade beans. The mean yield of Teebus is lower than that of the best entries, but is well adapted in North West and the eastern Free State. Teebus-RR1 had the highest mean yield over three seasons. It is similar to Teebus but is resistant to rust and is widely adapted. The canning quality of PAN 185 and OPS-KW1, is acceptable to canners. Both have a high mean yield and yield reliability, and are widely adapted. Teebus-RCR2 is a new cultivar that is similar to Teebus but is resistant to rust and common blight. It is still undergoing factory canning tests. PAN 123 had the second-highest mean yield over three seasons and good disease resistance. It is still undergoing factory canning tests.
Red speckled beans Although there is a good market for red speckled beans, the market can discriminate against cultivars with small seeds or a dark background colour. Cultivars of which seed is available: long-season cultivars with the highest mean yield, yield reliability, good seed quality and disease resistance are PAN 128, OPS-RS4, Kranskop-HR1, PAN 116, OPS-RS1, Jenny, DBS 310, PAN 118, PAN 148, Kranskop, and DBS 360 and OPS-RS2. Yield differences in this group can be as high as 0,35t/ha. PAN 135 (lodging resistant) has a lower yield than the former group. It was not included in this season’s trials but seed is available. In this group PAN 118, DBS 360 and PAN 148 have the smallest seeds while PAN 9249 and Jenny have the largest seeds. PAN 116 and OPS RS2 have excellent lodging resistance. PAN 9249 (large seeds and high yields over three seasons) and PAN 139 will be available next season. RS5 (lodging resistant) had high yields over a number of seasons. Bonus is susceptible to rust and has a lower yield potential than the rest of the long-season cultivars. It was included as a control. Two new high-potential long-season cultivars were included for the second season – Sederberg (sixth-highest mean yield) and PAN 9257.
Carioca beans The market for Carioca beans is limited and producers must assure themselves of a market before planting. Mkhuzi had very high yields and yield reliability is widely adapted. It has high levels of resistance to nearly all diseases. This cultivar is recommended for KZN because of its disease resistance. Other seed types Painted Lady (cultivar Maskam) is mainly produced in the Western Cape under irrigation because of its disease susceptibility and quality requirements. • • Large white kidney beans There is a limited local market for large white kidney beans. They fetch high prices in seasons when overproduction does not occur. SSN1 (not included in trials) is the only cultivar in this seed type. Kidney beans are sensitive to high temperatures during flowering. They are only recommended for the cool, high-rainfall areas where high yields can be obtained. Because of their disease resistance, kidney beans are well adapted to these areas. Order the Dry Bean Production Manual from the Dry Bean Producers’ Organisation or ARC-GCI. For updated information on registered fungicides, insecticides and herbicides visit www.arc.agric.za. |fw
