Suntaree Surson, Suwit Laohasiriwong, Preecha Prathepha, and Sopone Wongkaew

pp. 807 - 822

Abstract

Inheritance study of groundnut indicated that a single dominant gene governed the flower with red
stripe on standard. All F₁ plants had red stripe on standard. The segregation of F_3:2 families (derived from
individual F₂ plants) showed 1:2:1 expected ratio (χ² = 0.659) of 1 non-segregating (plants with red stripe on
standard) to 2 segregating (plants with red stripe on standard and plants with no red stripe on standard) to
1 non-segregating (plant with no red stripe on standard). When the F₃ groundnut families which had plants
with red stripe on standard were combined, the segregation ratio was not different from the 3:1 Mendelian
ratio (χ² = 0.073). The symbols for standard flower trait were designated St for dominant trait and st for recessive trait. For peg's color characteristic, the plants with red stripe on standard flower had purple peg.
It is possible that the red stripe on standard flower gene had a pleiotropic effect on peg color or this may
indicate linked genes. For characters of pod, the F₁ showed moderately reticulate pods.The segregation of
F_3:2 families showed also a 1:2:1 expected ratio (χ² = 0.067) giving 1 non-segregating (plants with reticulate
pod) to 2 segregating (plants with reticulate pod and plants with smooth pod) to 1 non-segregating (plants
with smooth pod). When the F₃ groundnut families which had plants with reticulate pod were combined, the
segregation ratio was not different from the 3:1 Mendelian ratio (χ² = 0.065). The results indicated that pod
characters were governed by a single gene. The symbols of pod character were designated Re for dominant
gene and re for recessive gene.
For yield components study, the F₃ generation had lower yield than their parents did but some of
them had similar yield with their parents. Yield components were highly correlated with each other. In
addition, yield components of F₃ families were also correlated with their leaf characters. The plants with
larger leaf had bigger pods, more prolific pods, and heavier seeds.