SPRING bean growers should be prepared to move to longer-strawed, later varieties, according to Cathy Knott of the Processors and Growers Research Organisation. "They have been more productive in recent dry seasons when lateness of harvest has not been a problem," she explains.
Among the fully recommended varieties, Victor, with a yield rating of 98, accounts for the largest seed area. But Mars (102) is taller and slightly later. It may be less sought after for export but is reliable and consistent, says Ms Knott.
Scirocco (99) has been popular because of its earliness. With premium export potential, if samples are free of Bruchid beetle, it has more than a quarter of the seed area. White-flowered Vasco (97) is outstripped for yield by all six provisionally recommended varieties, including two similarly low tannin types.
Big premiums – up to £60/t – for pigeon feed continue to be offered for good quality samples of Maris Bead (86) which has been on the list since 1964.
"According to suppliers there is a large home and export market, which often has to be filled with Canadian or Australian imports." Above average 1996 yields and low inputs because of good disease resistance could generate renewed interest in the variety, she believes.
Of the newer types Maya (106) was disappointing in 1996 trials and stays provisionally recommended for a further year. "It is high yielding but has short straw."
Newly-listed Merkur (also 106) is very tall, average height 143cm (56in), leafy and vigorous. "It could lodge in a wet season. It is best suited to light soils, and fertile conditions should be avoided." Downy mildew resistance is good.
Late maturing Corvette (105) could also lodge in wet years, says Ms Knott. "But it has yielded very well in drought conditions." Aribo (103), another late variety, is very susceptible to downy mildew.
White-flowered types Alpine (99) and Avon (98) have a slight yield edge over Vasco and both are taller. "Alpine has an advantage with slightly better downy mildew resistance. Avon is very early." Caspar (96) is becoming outclassed.
Alfred, "an old friend" and forerunner of the new generation of spring beans, is no longer listed. *
Spring bean yields have suffered in two successive dry years.