|Carrajol, Jose - UNIV OF PUERTO RICO|
Submitted to: Nematropica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 1, 2002
Publication Date: December 1, 2002
Citation: SMITH, J.R., CARRAJOL, J.C. HOST SUITABILITY OF PIGEON PEA FOR HETERODERA GLYCINES RACE 2. NEMATROPICA. 2002. vol. 32(2). p. 125-130. Interpretive Summary: Among the ten countries that produce nearly 98% of the world's soybean crop, soybean cyst nematode causes more yield loss than any other disease of soybean. Soybean cyst nematode (race 2) was recently discovered in Puerto Rico, where pigeon pea is the most widely grown edible legume. Pigeon pea is an important source of protein for over a billion people in the world and is India's second most important pulse crop. Soybean and pigeon pea acreage overlap in India, where soybean cyst nematode could be a potential problem if introduced. However, the effect of soybean cyst nematode on pigeon pea is unknown. This study demonstrated that pigeon pea is a poor host for race 2 soybean cyst nematode and that it will likely not suffer any yield loss due to soybean cyst nematode in Puerto Rico, India or other parts of the world. This information will benefit farmers who grow or may grow soybean and pigeon pea in areas infested with soybean cyst nematode. It may be possible to use pigeon pea as a rotation crop for soybean in order to reduce the number of nematodes in an infested soil.
Technical Abstract: Heterodera glyicnes (soybean cyst nematode) is the most destructive pathogen of soybean (Glycine max) in the world, but its impact on pigeon pea (Cajanus cajan) is unknown. H. glycines was discovered in Puerto Rico,where pigeon pea is the most widely grown edible legume. Information on the host suitability of pigeon pea for H. glycines is necessary to ensure the continued sustainable production of pigeon pea and to determine if alternate production strategies may be necessary in the future. The purpose of this research was to determine the host suitability of pigeon pea for H. glycines. Ten pigeon pea cultivars were evaluated in three assays (two field and one greenhouse) for host suitability to the Isabela, Puerto Rico race-2 population of H. glycines. Field assays involved a one- replication potted trial and a two-replication field-dug trial, both using an infested 'Coto' clay soil. The greenhouse assay consisted of a six- replication potted experiment using an artificially-infested gravelly sand loam soil. A minimal number of white females were observed on four pigeon pea cultivars ('I-8-3-2', 'I-13', 'Cortada', and 'II-56') in the infested field assays, while none were observed on the other six ('PR-147', 'I-58- 3', 'Blanco de Yauco', 'Guerrero', 'I-8-3-1', and 'Kaki'). No H. glycines reproduction occurred on any pigeon pea cultivar in the artificially- infested greenhouse assay. Although additional studies with other cultivars and races may be necessary to verify these initial conclusions, the current data indicate that the four varieties on which H. glycines reproduction occurred are very resistant, while the other six might be considered immune. Pigeon pea is a poor host for H. glycines and will likely not suffer any yield loss due to the Puerto Rico race-2 population.