Biomass partitioning of cacao (Theobroma cacao L.) was studied in seven clones and five hybrids in a replicated experiment in Bahia, Brazil. Over an 18-month period, a 7-fold difference in dry bean yield was demonstrated between genotypes, ranging from the equivalent of 200 to 1389 kg·ha-1. During the same interval, the increase in trunk cross-sectional area ranged from 11.1 cm2 for clone EEG-29 to 27.6 cm2 for hybrid PA-150 × MA-15. Yield efficiency increment (the ratio of cumulative yield to the increase in trunk circumference), which indicated partitioning between the vegetative and reproductive components, ranged from 0.008 kg·cm-2 for clone CP-82 to 0.08 kg·cm-2 for clone EEG-29. An examination of biomass partitioning within the pod of the seven clones revealed that the beans accounted for between 32.0% (CP-82) and 44.5% (ICS-9) of the pod biomass. The study demonstrated the potential for yield improvement in cacao by selectively breeding for more efficient partitioning to the yield component.
A.J. Daymond, P. Hadley, R.C.R. Machado, and E. Ng
James Nienhuis, Jan Tivang, Paul Skroch, and Joao B. dos Santos
Knowledge of relative genetic distance among genotypes is useful in a breeding program because it permits organization of germplasm resources. Genetic distance (GD) was estimated among 65 Phaselous lunatus L.. accessions, which included 4 large-seeded and 7 small-seeded cultivars and 54 germplasm accessions (landrace's) from the Caribbean and North, Central, and South America. Based on 125 polymorphic random amplification polymorphic DNA (RAPD) bands, two major clusters, which generally correspond in seed size and geographic region to [be Mesoamerican and Andean gene pools, were observed among the landraces (GD = 0.726 ± 0.041). Four Fordhook cultivars and a landrace from the United States formed a separate cluster that is more distantly related to the small- (GD) = 0.561 ± 0.039) than to the large-seeded cluster (GD = 0.303 ± 0.022). The mean GD between the Andean and Mesoamerican (0.726), Mesoamerican and Fordhook (0.561), and Andean and Fordhook (0.303) clusters were all significant. The significant GD between the Andean and Mesoamerican groups supports the hypothesized existence of two major gene pools in lima bean. The RAPD marker diversity of the Mesoamerican group was the largest (0.1 10), followed by the Andean (0.097) and Ford hook (0.062) groups. The plot of the relationship between the coefficient of variation (cv) and sample size (number of bands) indicates that cvs as low as 10% for estimating CD between Andean and Mesoamerican lima bean accessions can be achieved by sampling as few as 100 bands.
Mark J. Bassett
The inheritance of novel flower and seedcoat patterns was studied in three parental materials: PI 390775 and `Springwater Half Runner' (SHR), which have patterned flower and seedcoat colors, and 5-593, a Florida dry bean breeding line with unpatterned purple flowers and seeds. Using crosses between 5-593 and the other two parents, an analysis of F1, F2, backcross F2, and backcross F3 data demonstrated that a single recessive allele in each of the patterned parents controlled flower and seedcoat pattern. Genetic tester stocks were used to demonstrate that the recessive gene for patterning in PI 390775 was nonallelic with C, T, and Mar, the three genes previously known to control seedcoat pattern in common bean. An allelism test between the recessive pattern genes from PI 390775 and SHR demonstrated that they were allelic and that the gene from SHR was dominant. The gene symbols stp (for the gene from PI 390775) and stp hbw (for the dominant gene from SHR) are proposed, where stp stands for stippled seedcoat pattern and the superscript letters hbw stand for half banner white.
Frank M. Elia, George L. Hosfield, James D. Kelly, and Mark A. Uebersax
. Elia in partial fulfillment of the requirements for the PhD degree at Michigan State Univ. Research supported by USDA, ARS, the Michigan Agricultural Experiment Station, and USAID/BIFAD under Bean/Cowpea CRSP grant no. DAN-1310-G-SS-6008-00. Names are
K.S. Yourstone and D.H. Wallace
1 Former Graduate Research Assistant. Current address: Dept. of Vegetable Crops, Cornell University, Ithaca, NY 14853. 2 Professor. Part of a PhD dissertation by K.S.Y. Department of Plant Breeding and Biometry paper no. 771. This research was
K.S. Yourstone and D.H. Wallace
1 Former Graduate Research Assistant. Current address: Dept. of Vegetable Crops, Cornell University, Ithaca, NY 14853. 2 Professor. Part of a PhD dissertation by K.S.Y. Department of Plant Breeding and Biometry paper no. 772. This research was
B.T. Scully, D.H. Wallace, and D.R. Viands
of the requirements of the PhD degree. Research supported by USAID Title XII Bean/Cowpea CRSP, Hatch Act funds, and the New York State Agriculture Experiment Station. Plant Breeding paper No. 791. The cost of publishing this paper was defrayed in part
Patrick D. O'Boyle, James D. Kelly, and William W. Kirk
acutifolius L. (tepary bean) and Phaseolus coccineus L. (scarlet-runner bean) have been identified and used in bean breeding programs. The development of gene pyramids consisting of resistance from various genetic backgrounds has been suggested as the most
Nirmal K. Hedau, Shri Dhar, Vinay Mahajan, Hari S. Gupta, Karambir S. Hooda, and Vedprakash
foothills to higher hills (northwestern Himalayan regions) and North Indian plains (subtropical zone) in different seasons of the year. In India, the French bean breeding program was strengthened with the commencement of the All India Coordinated Research
Wei-Ling Chen and Hsueh-Shih Lin
2 to 3 months for concentrated production. Nevertheless, this can afford relatively little competition to their companion crops ( Hyman et al., 2008 ). The objectives for common bean breeding focus primarily on improving yield, quality, environmental