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S. Kuruvadi and I. Sanchez Valdez. 1993. Range of yield components and phenotypic correlations in tepary beans (Phaseolus acutifolius) under dryland conditions. p. 594-596. In: J. Janick and J.E. Simon (eds.), New crops. Wiley, New York.

Range of Yield Components and Phenotypic Correlations in Tepary Beans (Phaseolus acutifolius) Under Dryland Conditions

Sathyanarayanaiah Kuruvadi and Isaac Sanchez Valdez

  1. METHODOLOGY
  2. RESULTS AND DISCUSSION
  3. REFERENCES
  4. Table 1
The genus Phaseolus mainly comprises four cultivated species: P. vulgaris, P. coccineus, P. acutifolius, and P. lunatus (Smartt 1979). Tepary bean (P. acutifolius) is highly resistant to drought (Nabhan and Felger 1978), useful as a source of disease, and drought resistance through interspecific hybridization with the common bean (Thomas et al. 1983). This species is distributed in the arid and semiarid regions namely: Arizona and New Mexico in the United States; and Baja California, Sonora, Chihuahua, Sinaloa, and Durango in Mexico. Seeds contain 23 to 25% proteins and produce higher yields when compared to several legume crops under extreme drought conditions. This legume possesses a broad spectrum of variability for yield and its components and has potential to become a new commercial crop. Tepary bean has not been extensively studied with respect to genetics, breeding, physiology, and agronomy. The objective of this investigation was to study the range of variability of yield and its components and to estimate phenotypic correlations between different pairs of characters.

METHODOLOGY

Sixteen accessions of tepary bean with a broad spectrum of variability were originally collected from five provinces in Mexico: 10 from Sonora (accession number 65, 74, 79, 84, 86, 99, 106, 112, 113, 121); two from Chihuahua (127, 129); and one each from Chiapas (39), Morelos (44), Campeche (49); and accession 46 from Guatemala. Four control cultivars ('Chapingo 24', 'Chapingo 25', PI 231638, and PI 319551) were included for comparison. All lines were seeded in a randomized block design with three replications at the Agricultural Experimental Station, Francisco I. Madero, Durango, Mexico. Each plot consisted of 4 rows, 6 m long, 76 cm between rows and 10 cm between plants within a row. Seeding was done in the first week of July during the monsoon season. Plant growth depended entirely upon natural precipitation and neither fertilizer nor irrigation were applied. The total precipitation received during the crop period was 48.9 cm. A five-plant random sample was taken in the middle two rows in each plot and observations were recorded on biometrical characters.

RESULTS AND DISCUSSION

Significant differences were found in yield, pods/plant, seed/pod, 100 seed weight, plant height, days to flower, and physiological maturity between genotypes revealing considerable genetic variability for these traits. Seed yield varied from 255 to 553 kg/ha with a mean of 387 kg/ha (Table 1). Line 86 produced the maximum grain yield (533 kg/ha) followed by the accession 106 (519 kg/ha). These two genotypes manifested 11.1 and 4.2% higher grain yield over the best check (PI 319551) and also demonstrated drought resistance based on grain yield.

Yield is a product of several yield components including the number of pods/plant, seeds/pod and seed weight. These components are generally the product of sequential development processes (Heinrich et al. 1983). The complex character yield has to be improved by improving the yield components. The number of pods/plant, a very important yield component, ranged from 8.1 to 37.1 among genotypes with a mean of 23.3. This trait showed very wide variation. Line 121 produced the maximum number of pods/plant (37.1) and lines 106, 113, 86, and 84 produced between 29 to 35 pods/plant. Normally pods/plant will have a tendency to increase with environmental improvements.

The number of seed/pod is a very prominent character, influencing yielding ability. This trait ranged from 3.1 to 5.8 with the check cultivar, 'Chapingo 24', recording the highest value. Other promising lines include accession 127, 49, and PI 319551. The variation for 100 seed weight was relatively narrow (10.6 to 12.8 g); accessions 49, 84, 6, 121, and PI 231638 had higher seed weights. Lines 49, 79, 86, 99, 113, and PI 231638 were the earliest in maturity. A combination of desirable traits were not centered in a single genotype but were distributed over several genotypes. Hybridization between genotypes with higher grain yield and superior lines for yield components could result in desirable recombinations in the progeny.

The broad-sense heritability estimates were 0.998 for seed weight, 0.936 for pods/plant, and 0.886 for seeds/pod, indicating that these characters are amenable to selection. Grain yield was highly significant and positively associated with pods/plant and seed weight. Weber and Moorthy (1952) and Johnson et al. (1955) obtained positive and significant correlations between yield and seed weight in soybeans. Kuruvadi and Escobar (1987) observed association between yield and pods/plant in common bean. Selection for pods/plant, seed/pod, and seed weight individually or simultaneously should increase yielding ability of the genotypes provided they are not inversely correlated.

REFERENCES

Table 1. Mean values for different agronomic characters in tepary beans under dryland conditions.

Accesion no. and cultivar Seed yield (kg/ha) No. pods/plant No. seeds/pod 100 seed weight (g) Plant height (cm) Days to flower Days to maturity
39 327 8.1 3.1 11.1 12.9 68.7 110
44 476 9.8 4.4 12.2 14.3 59.3 110
46 337 4.5 3.3 11.0 13.3 68.0 107
49 255 27.7 5.4 14.3 13.1 58.7 94
65 353 21.3 5.2 11.3 13.6 62.3 100
74 369 24.3 5.2 11.3 17.5 63.0 105
79 370 19.1 5.3 10.6 14.0 51.0 95
84 364 28.7 4.7 12.8 18.4 52.3 89
86 553 30.2 4.6 12.7 16.0 49.7 94
99 379 23.5 5.1 11.8 14.8 57.3 96
106 519 35.2 5.1 11.7 18.0 53.7 97
112 350 22.8 5.2 11.9 15.8 58.0 103
113 362 32.9 4.3 12.1 13.7 52.7 93
121 484 37.1 4.5 12.3 14.5 51.0 96
127 334 20.4 5.6 11.6 17.4 62.7 103
129 453 23.0 5.1 11.6 14.9 60.7 103
Chapingo 24 331 22.6 5.8 11.3 13.9 53.3 94
Chapingo 25 296 19.3 5.2 11.2 17.9 60.0 108
PI 231638 338 23.1 5.1 12.5 13.4 51.7 94
PI 319551 498 31.2 5.4 11.9 13.3 53.7 100
Mean 387 23.3 4.8 11.9 15.0 57.6 99
DMS 5% 101 9.3 0.5 1.1 4.2 13.2 13

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