OAC Thunder - CULTIVAR DESCRIPTION

T. E. Michaels and T. H. Smith
Department of Plant Agriculture, University of Guelph, Guelph, Ontario Canada N1G 2W1

Michaels, T.E. and Smith, T.H. 1998. OAC Thunder whitebean. OAC Thunder is a mid-maturity whitebean (Phaseolus vulgaris L.) cultivar with excellent yield potential and is intended for use in either wide or narrow row production.

The white seeded common bean (Phaseolus vulgaris L.) cultivar OAC Thunder was developed by the Department of Crop Science, University of Guelph, Guelph, Ontario. It is intended for production in areas of Ontario with more than 2600 corn heat units (CHU). OAC Thunder was issued Registration No. 4491 on 3 March 1997 by the Registrar, Variety Registration Office, Plant Products Division, Agriculture and Agrifood Canada, Nepean, Ontario.

Pedigree and Breeding Methods

OAC Thunder, tested as OAC 93-1, was derived from the cross Ex Rico subline 1351 x W84-129 made in 1986 in an indoor growth room. Ex Rico subline 1351 is a breeding line with pedigree ExRico 23 *5 // Ex Rico23 / Narda. W84-129 is an F3 single plant selection made in 1985 from a population with the pedigree T81-01 / Domino // Ex Rico are / Domino /3/ NZUpright / Sacremento Light Red Kidney. F1 plants were grown in the field at the Elora Research Station and all seeds were bulked. The F2 to F5 generations were advanced using the single pod descent (pod bulk) method utilizing a winter nursery in New Zealand in the winters of 1986-87 and 1987-88. Single plant selections for early maturity, upright plant architecture, white bean seed type and high pod number were made on space planted F5 plants in the field at Elora, Ontario in 1988. F6 progeny rows were grown in single row plots at the Elora Research Station in 1989 where single rows were selected for the same agronomic traits. F7 and F8 generations were grown in 1990 and 1991 at Woodstock and Elora, Ontario in field yield trials, where selection was for the same agronomic traits plus seed yield under conventional and narrow row production with direct combining. The line OAC 93-1 was identified in these trials and entered in the Ontario Pulse Committee's White Bean Trials in 1993 and 1994. One hundred plants were grown in the winter of 1994-95 in a growthroom from residual F6 seed, and the progeny of those plants were sent to Twin Falls, Idaho, USA for breeder seed production in 1995 and 1996. Breeder seed plots were rogued for uniformity and trueness to type, and seed from the remaining plants were bulked to produced breeder seed.

Performance

OAC Thunder matured approximately 2 days earlier than OAC Laser, and outyielded OAC Laser by 45 kg/ha over 20 environments in 3 years (Table 1). OAC Thunder is an indeterminate bush plant with erect stem and branches, and a vine similar in length to that found on OAC Gryphon. The cultivar can be successfully produced in either traditional wide (70cm) rows or narrower (< 40cm) rows with direct combine harvesting.

Other Characteristics

OAC Thunder has a green hypocotyl in the seedling stage and white flowers which appear approximately 45 days after planting. Pods at maturity are light beige, although faint purple flecking may occur in some environments. Leaves are larger than those of OAC Speedvale, and similar to OAC Gryphon in both size and grey-green colour. Seeds are dull white in colour and similar in size to OAC Cygnus. Cooking quality was judged acceptable and similar to Centralia (Table 2).

Pedigreed Seed Stock

Breeder seed of OAC Thunder is maintained by the Department of Crop Science, University of Guelph, Guelph, ON, Canada N1G 2W1. Pedigreed seed is distributed through SeCan Association, 501-300 March Rd., Kanata, ON, K2K 2E2.

The authors gratefully acknowledge the technical assistance of Judy Krusky; and the cooperative yield trials conducted by Soon Park, Chris Gillard, John Van Herk and John Madill; and the financial support provided by the Ontario Ministry of Agriculture and Food and Rural Affairs, and the Ontario Bean Producers= Marketing Board.