Table 3.
Growth habit, seed color, and ashy stem blight mean scores for four pyramided common bean (Phaseolus vulgaris L.) breeding lines, their parents/known sources of resistance, and susceptible checks evaluated against PRI21 Macrophomina phaseolina (Tassi) Goidanich isolate at 42 and 21 days after inoculation in the greenhouse and the field in Isabela and Lajas, Puerto Rico, in 2021.
| Genotype | Growth habit a | Seed color | Greenhouse | Field | |||||
|---|---|---|---|---|---|---|---|---|---|
| Isabela April | Lajas February | Isabela May | Lajas September | ||||||
| Severity | Mean | Severity | Mean | ||||||
| New breeding lines with partial resistance to ashy stem blight | |||||||||
| UPR-Mp-22 | I | Cream-mottled | 4.6 | 3.8 | 4.2 | 5.0 | 4.5 | 4.8 | |
| UPR-Mp-34 | III | Cream-colored | 3.9 | 3.9 | 3.9 | 6.0 | 4.1 | 5.0 | |
| UPR-Mp-42 | I | Black | 5.3 | 5.4 | 5.3 | 5.0 | 4.9 | 5.0 | |
| UPR-Mp-48 | I | White | 4.2 | 4.4 | 4.3 | 5.9 | 4.7 | 5.3 | |
| Parental genotypes and breeding lines reported with resistance to ashy stem blight | |||||||||
| A 195 | I | Beige opaque | 3.8 | 4.6 | 4.2 | 5.7 | 6.4 | 6.1 | |
| BAT 477 | III | Cream-colored | 7.1 | 6.4 | 6.8 | 6.4 | 7.3 | 6.8 | |
| NY6020-4 | I | White | 7.0 | 7.3 | 7.1 | 6.7 | 7.8 | 7.3 | |
| ‘PC 50’ | I | Red-mottled | 4.1 | 4.8 | 4.5 | 6.3 | 6.7 | 6.5 | |
| PRA154 | I | Beige-mottled | 4.1 | 4.4 | 4.3 | 5.1 | 4.6 | 4.8 | |
| PRA155 | I | Cream with black spots | 5.9 | 4.0 | 5.0 | 6.4 | 3.9 | 5.2 | |
| SEA 5 | III | Cream-colored | 7.0 | 6.6 | 6.8 | 7.1 | 7.7 | 7.4 | |
| TARS-MST1 | II | Black | 7.0 | 8.5 | 7.8 | 7.3 | 8.7 | 8.0 | |
| XAN 176 | III | Black | 6.2 | 7.1 | 6.6 | 6.1 | 7.5 | 6.8 | |
| Susceptible checks | |||||||||
| ‘Bella’ | II | White | 7.1 | 7.6 | 7.4 | 7.0 | 8.6 | 7.8 | |
| ‘Verano’ | II | White | 7.0 | 9.0 | 8.0 | 7.5 | 8.0 | 7.8 | |
| Mean | … | … | 5.6 | 5.9 | 5.8 | 6.2 | 6.4 | 6.3 | |
| LSD (P ≤ 0.05) | … | … | 1.5 | 1.2 | 1.0 | 1.0 | 0.9 | 0.8 | |
a
Growth habit, where I = determinate upright, II = indeterminate upright, III = indeterminate prostrate semiclimbing (Singh, 1982).
Ashy stem blight disease severity was scored on a 1–9 scale, where 1–3 = resistant, 4–6 = intermediate, and 7–9 = susceptible (Viteri & Linares, 2017).