Testers for combining ability and selection of papaya hybrids resistant to fungal diseases

Abstract

'JS 12' with 'Sunrise Solo' and 'Kaphoro Solo PV'; tester 'Americano' with 'Caliman M5', 'Sunrise Solo', 'Baixinho de Santa Amália' and 'Waimanalo'; and tester 'Maradol' with 'Caliman G', 'Caliman AM' and 'Sunrise Solo PT'. These results may be useful in breeding for disease resistance by hybridization.

Selecting black-spot resistant papaya genotypes derived from backcrossing and hybrids

“…Thus, this indicated that such parents may present low severity and help to reduce the disease in crossings. Vivas et al (2011) selected promising black-spot resistant hybrids in crossings between SEKATI and Sunrise Solo (SS-72/12), which corroborates the results found in the current study. According to the results obtained in the current study, the L-6 and L-9 lines, which were derived from the genotype 'Cariflora', also have breeding potential for disease resistance since their crossings showed the lowest means for disease intensity and incidence (Table 1).…”

“…Studies have shown that, although the low heritability is not significant, it is possible to achieve successful plant breeding in terms of disease resistance (Vivas et al, 2011(Vivas et al, , 2014. This is because the differences in the heritability estimates must be interpreted as being specific to the studied genotypes and environments rather than as a fixed attribute of the assessed phenotypic feature (Allard, 1971).…”

“…The severity of black spot in the leaves was estimated through the diagrammatic scale adopted by Vivas et al (2011), according to the following proportions of injured areas: 0.2, 1.6, 3.5, 5.4, 7.6, and 12.8%. Black-spot severity was assessed in leaves in which the petiole presented the first newly open inflorescence.…”

Incidencia y severidad de la antracnosis en líneas e híbridos de papaya (Carica papaya).

“…Vivas et al (2011) encontraron una contribución de algunas líneas a la resistencia de la antracnosis en las frutas; estos autores consideran que los híbridos y líneas más resistentes aportaron un avance importante en cuanto a la disminución de pérdidas poscosecha. solano y arauz (1995); reportan un 90% de incidencia, así como una severidad del 13%, después de seis días de cosecha en el tratamiento testigo (sin ninguna aplicación de fungicidas), en variedades criollas, sembradas en esta misma zona.…”

Optimal plot size in the evaluation of papaya scions: proposal and comparison of methods

“…There are reports of the use of only one plant per plot (Pratissoli et al, 2007;Melo et al, 2009) to 20 plants per plot (Vivas et al, 2011). In trials with production of papaya seedlings in nursery, useful sizes of plots follow the same arbitrariness, also due to the lack of studies on plot designs.…”