Potential Grain and Forage Production of Early Maturing Pigeonpea in the Southern Great Plains

byproducts may be available for incorporation into animal feeds (Whiteman and Norton, 1981). Pigeonpea Forage-based livestock production is a significant component of biomass and grain have been used as animal feed for the agricultural economy throughout the southern U.S. Great Plains. However, Livestock production in grazing systems is limited by low centuries by Indian farmers (Whyte et al.,1953; Pathak, forage mass and quality from late July to early November. Pigeonpea 1970). Febles and Padilla (1970) reported yields of 7.8 (Cajanus cajan L. Millsp.) is a warm-season grain legume that may Mg ha 1 of green pods, roughly equivalent to 3.9 Mg have potential as a summer forage crop. A 3-yr (1996–1998) field ha 1 of grain, from high-yielding cultivars in Puerto study was conducted near El Reno, OK, to assess the performance Rico. Phatak et al. (1993) evaluated over 60 early and of two early maturing pigeonpea lines, Georgia-2 and ICPL 85010. medium-maturing lines in Georgia and Mississippi that The two lines did not differ significantly in forage and grain production were acquired from ICRISAT. Six of the lines produced and nutritive value. At 96 d after planting (DAP), total aboveground 4 Mg of grain ha 1. Sheldrake and Narayanan (1979) biomass was 5.2 Mg ha 1, N content was 23 g kg 1, and in vitro reported pigeonpea grain yields of 0.5 to 1 Mg ha 1 yr 1 digestible dry matter (IVDDM) was 580 g kg 1 averaged across years. under limited rainfall, and 1.6 to 2.5 Mg ha 1 under At final harvest (118 DAP), total dry biomass was 12.6, 6.4, and 9.3 Mg ha 1 in 1996, 1997, and 1998, respectively. Seed yield was 5.4, more favorable growing conditions. 1.9, and 1.2 Mg ha 1 in 1996, 1997, and 1998, respectively. Nitrogen Because grain can be produced under relatively adconcentration and IVDDM at final harvest was 19 and 585 g kg 1 for verse climatic conditions, pigeonpea can be grown in total plant biomass, 34 and 758 g kg 1 for leaves, 9 and 420 g kg 1 areas not suitable for soybean [Glycine max (L.) Merr.] for stems, and 26 and 750 g kg 1 for seed, respectively. Early maturing (Wallis et al., 1988). In addition, pigeonpea can also pigeonpea lines can fill the forage deficit period during late summer reduce soil erosion (Morton, 1976; Sheldrake and Naraand provide protein supplement for livestock. yanan, 1979; Ong and Daniel, 1990). The objective of the study was to determine the biomass and grain yields and nutritive value of two early maturing pigeonpea P is an important grain legume crop grown lines grown during the summer fallow period of continuin tropical and subtropical regions (Nene and Sheila, ous winter wheat production in the southern Great 1990). It can survive well in degraded soil and is drought Plains. tolerant. However, traditional varieties are highly sensitive to photoperiod (McPherson et al., 1985) and take MATERIALS AND METHODS from 175 to 280 d to reach maturity. In temperate reThe study was conducted during the summer fallow period gions, such varieties cannot be grown successfully bebetween continuous winter wheat crops at the Grazinglands cause of exposure to frosts during the latter part of the Research Laboratory near El Reno, OK (35 40 N, 98 00 W, growing season. In recent years, early maturing lines elevation 414 m). Soil on the experiment site was Dale silt were developed at the International Crop Research Inloam (fine-silty, mixed, superactive, thermic, Pachic Haplusstitute for the Semi-Arid Tropics (ICRISAT). These tolls) with a pH of 6.6. Mean maximum and minimum temperanew lines are relatively photoperiod insensitive and tures at this location during the June to September growing mature in 125 to 140 d (Singh et al., 1990). Ali (1990) season are 36 C and 20 C, respectively. The 25-yr mean averreported that in northern India, early maturing piage rainfall during the growing season (May to September) geonpea lines can be successfully grown in rotation with is 500 mm. Average date of the first killing frost (90% probability) is 11 November (Johnson and Duchon, 1995). winter wheat. Early and medium-maturing pigeonpeas Two early maturing pigeonpea lines were selected for study. were successfully used for cattle grazing as well as forage These were Georgia-2, developed at the University of Georand seed production (Akinola and Whiteman, 1975). gia, Tifton, GA; and ICPL 85010, which was developed at It was recently demonstrated that Pigeonpea grain ICRISAT, Patancheru, A.P., India. Both lines are early maturfrom early maturing line GA-2 can be used as a protein ing (110–140 d to reach maturity), photoperiod insensitive, supplement for livestock (Phillips and Rao, 2001). The short-statured, and determinate in growth habit. Following major market for good-quality pigeonpeas are for huwheat grain harvest in June, plots were prepared with convenman consumption in most parts of Asia and Middletional tillage and 26 kg ha 1 of P were applied. No N fertilizer eastern countries, but cracked and pinched grain and was applied. Each plot was 3-m wide and 20-m long, with three replications of each line. Seeds were inoculated with a multistrain inoculum commonly used for cowpeas and planted S.C. Rao, W.A. Philips, and H.S. Mayeux, USDA-ARS, Grazinglands ≈2 cm deep at the rate of 30 kg ha 1 with a row spacing of Research Laboratory, 7207 W. Cheyenne St., El Reno, OK 73036; S.C. Phatak, Dep. of Hortic., Univ. Of Georgia, Tifton, GA 31793. 60 cm and an in-row spacing of 15 cm. Planting dates were 6 Received 5 Nov. 2002. *Corresponding author ([email protected]. gov). Abbreviations: CGR, crop growth rate; DAP, days after planting; ICRISAT, International Crop Research Institute for the Semi-Arid Published in Crop Sci. 43:2212–2217 (2003).  Crop Science Society of America Tropics; IVDDM, in vitro digestible dry matter; NIRS, near-infrared reflectance spectroscopy. 677 S. Segoe Rd., Madison, WI 53711 USA