by Glenn I. Teves, County Extension Agent
UH CTAHR Cooperative Extension Service
In the 1940’s, the main pole bean variety in Hawaii was Kentucky Wonder, but in many parts of Hawaii, especially in wet areas, Rust Fungus Uromyces appendiculatus was a big problem. A foliar disease with orange pustules on the lower surface of leaves, it can defoliate the plant leading to decreased production and early death. UH vegetable breeders Walter ‘Tex’ Frazier and John Hendrix decided to tackle the problem by crossing Kentucky Wonder with a rust-resistant bush bean developed in the late 1800’s by Peter Henderson & Company called ‘Bountiful’ to create a new rust-resistant pole bean they named ‘Lualualei’.
To magnify the superior eating quality of ‘Kentucky Wonder’, ‘Lualualei’ was then crossed back to Kentucky Wonder to create ‘Hawaiian Wonder’.
Great breeders don’t rest on their laurels because they’re constantly playing catch up with a host of diseases waiting in line to devour the farmer’s crop, so root-knot nematode infestation was the next problem waiting to be solved. Of the four species of root-knot nematodes found globally, Meloidogyne incognita and Meloidogyne javanica are the most serious on vegetables in Hawaii. UH vegetable breeder Dick Hartmann came onto the scene and built on the success of Frazier and Hendrix’s ‘Hawaiian Wonder’ by crossing it with a variety called ‘Alabama No. 1’, a root-knot nematode resistant bean, to create ‘Manoa Wonder’.
In plant breeding, it’s not always a win-win because with something gained, usually something is lost.
‘Manoa Wonder’ wasn’t as resistant to rust fungus as ‘Hawaiian Wonder’ but provided protection from root-knot nematodes, a major plant nemesis on many crops in Hawaii. Now you had to choose what problem was the most pressing and selecting either ‘Hawaiian Wonder’ or ‘Manoa Wonder’ as your main variety.
Dick Hartmann moved to the next level by increasing disease resistance, and improving bean quality. A variety can have a very attractive disease resistance package but lack taste or in the case of beans be tough and have stringy pods. Tough bean pods may be able tolerate a lot of insect damage but are too fibrous and stringy for Tom and Susie Homemaker.
The next step was a little more complex and involved crossing a bunch of varieties together, not just a simple cross to combine disease resistance, tender pods, and good taste. Dick Hartmann grew and selected the crosses for 10 generations, a little more than is usually required to breed a new variety, in order to select for long tender pods with good disease resistance.
He started by adding in new genes from a Hungarian bean with unusually long pod length combined with a relative lack of strings on the pods. However, it had weak growth and poor productivity in Hawaii’s growing conditions, even when free of diseases. In life, you cannot have it all and sometimes you have to choose one over the other, and in the words of a Rolling Stones song, “You can’t always get what you want, but if try sometime you just might find, you get what you need.”
In life, you cannot have it all and sometimes you have to choose one over the other.
A group of progeny from this cross were selected and crossed with a highly nematode-resistant introduction from Mexico via Ferry Morse Seed Company and USDA Western Regional Plant Introduction in Pullman, Washington. After six generations of grow-out and selection, Dick Hartmann still couldn’t combine all the attributes he was seeking, so he did a backcross to ‘Manoa Wonder’.
You can expect Murphy’s Law to play into whatever breeding you’re trying to accomplish, especially when things are growing great. There was variability in flower color which would indicate either outcrossing or just a lot of variability in the line. Flower color can also be linked to resistance or susceptibility to other challenges. Most farmers want to have each plant germinate and mature around the same time to make harvesting more cost-efficient.
Six more generations of selection created the ‘Poamoho’ pole bean, named after the Poamoho Experiment Station near Oahu’s North Shore.
A huge advantage in creating new crop varieties in Hawaii is that it can be field tested in many locations, at different elevations with varied climatic schemes, simultaneously. In this way, its true colors over a range of climatic conditions will manifest itself. There were many more functioning UH field stations than we have today, and with adequate field crews, trials could be run in five locations. Results of field trials at Kapa’a on Kauai, Pulehu on Maui, Waiakea and Lalamilo on the Big Island, and Poamoho on Oahu, were interesting and varied, but in a few locations ‘Poamoho’ yielded almost double that of ‘Hawaiian Wonder’ and ‘Manoa Wonder’.
‘Poamoho’ is an improvement over its parent, ‘Manoa Wonder’, with a long straight flat pod, but is also stringless and tender even when older. It matures slightly earlier, yields significantly more, and is equal to 'Manoa Wonder' in resistance to root-knot nematodes and also tolerance of Rhizoctonia fungus, Rhizoctonia solani a root rot or damping-off fungus troublesome on emerging seedlings especially in wet conditions. ‘Poamoho’ has white seed compared to the brown-seeded ‘Hawaiian Wonder’ and ‘Manoa Wonder’.
By Glenn I. Teves
Glenn and Jane Teves are Hawaiian Homesteaders who farm on the island of Moloka'i, "we started growing vegetable seeds in 2011 after attending the first Hawaii Public Seed conference in Kona, and have planted seed crops in each season to learn and identify the best crops for our location."