Inheritance studies for pod shattering in cowpea (Vigna unguiculata L. Walp.)
No hay miniatura disponible
Fecha
Autores
Título de la revista
ISSN de la revista
Título del volumen
Editor
Bayero university Kano
Resumen
Descripción
This study was conducted to assess phenotypic variability in pod shattering among advanced cowpea genotypes and to elucidate the genetic inheritance of resistance to pod shattering. Thirty-six cowpea lines, including elite breeding lines and a wild relative, were evaluated under field conditions at the IITA Minjibir research station using a 6×6 alpha lattice design. Based on phenotypic screening, six parental lines were selected and crossed in a bi-parental mating scheme to generate three F1 populations, which were advanced to F2 in the screenhouse. The F2 populations were evaluated in the field based on a randomized complete block design. Data were collected on pod shattering and pod twist at physiological maturity, alongside other agronomic traits. Statistical analyses, including ANOVA, frequency distribution, segregation, heritability estimates, and character association studies, were performed using R and Microsoft Excel. The segregation patterns in the F2 populations revealed that pod shattering in populations 1 (IT17K-939-1-1 × IT17K-1267-2-1) and 2 (IT17K-939-1-1 × BB-POP-255-1) followed Mendelian inheritance models with 3:1, 13:3, and 9:7 ratios, indicating monogenic and digenic control with epistatic and complementary gene interactions. Population 3 (APH-1-143 × APH-1- 145) displayed complex segregation inconsistent with classical ratios, suggesting polygenic control. Broad-sense heritability (H2) estimates for pod shattering were high cross populations: 82% (Pop 1), 74% (Pop 2), and 100% (Pop 3), while pod twist showed variable heritability (79%, 41%, and 100%, respectively), indicating differential environmental influence. Character association analysis showed strong positive correlations between pod shattering and pod twist, suggesting pleiotropy or close linkage. The observed segregation patterns and heritability estimates imply that genetic improvement for resistance to pod shattering in cowpea will benefit from population specific selection strategies, particularly targeting recessive alleles and gene interactions involved in the pod dehiscence.
Palabras clave
population, segregation, heritability, cowpeas