![[Home Page]](/images/icons/gramene_logo180new.jpg "[Home Page]"){kind=icon}
rice
E.R. ANGELES and G.S. KNUSH
International Rice Research Institute, MCPO Box 3127, Makati
City 1271, Philippines
Eight genes for resistance to green
leafhopper (GLH), Nephotettix virescens (Distant) have so far been identified.
The dominant genes Gihi, G1h2, G1h3 (Athwal et a!. 1971) and G1h5 (Siwi
and Khush 1977) and the recessive genes glh4 (Siwi and Khush 1977) and
glh8 (Ghani and Khush 1988) govern resistance to GLH populations in the
Philippines. The dominant genes G1h6 and G1h7 (Rezaul Karim and Pathak
1982), on the other hand, confer resistance to Bangladesh populations of
GLH.
An IRRI developed variety, IR28,
also has a single dominant gene for resistance which segregated independently
of Gihi, G1h2 and G1h3 (Avesi and Khush 1984). This variety was used as
one of the testers in some studies on the inheritance of resistance to
green leafhopper (Ruangsook and Khush 1987; Ghani and Khush 1989). However,
the allelic relationships of the gene for resistance in IR28 with G1h5
were not known.
We, therefore, crossed IR28 with
ASD8, a variety known to have G1h5. F2 and F3 progenies were evaluated
for their reaction to Philippine population of GLH by bulk seedling test
(Athwal et a!. 1971). Of the 791 F2 seedlings tested, 751 were resistant
and the remaining 40 were susceptible. This segregation agreed with 15
resistant: 1 susceptible ratio (x2 = 1.92) expected for two dominant independently
segregating genes. Of the 154 F3 families of this cross tested for resistance,
59 were resistant, 87 segregating and 8 susceptible. These data agree with
the segregation ratio of 7 resistant:8 segregating: 1 susceptible (f =
2.61) expected for two independently segregating genes.
The results show that the dominant
gene for resistance to green leafhopper in IR28 is non-allelic to and independent
of GlhS. It is designated as G!h9(t).
Athwal, D.S., MD. Pathak, E.H. Bacalangco and C.D. Pura,
1971. Genetics of resistance to brown planthopper and green leafhopper
in Oryza sativa L. Crop Science 11: 747-750.
Avesi, G.M. and G.S. Khush, 1984. Genetic analysis of resistance
to the green leafhoper, Nephotettix virescens (Distant), in sonic cultivars
of rice, Oryza sativa L Crop Protection 3(1): 41-51.
Ghani, MU. and (J.S. Khush, 1988. A new gene for resistance
to green leafhopper, Nephotettix virescens (Distant), in rice. Journal
of Genetics 67(3): 15 1-159.
Rezaul Karim, &N.M. and M.D. Pathak, 1982. New genes
for resistance to green leafhopper, Nephotettix virescens (Distant), in
rice, Oryza sativa L. Crop Protection 1: 483-490.
Ruangsook, B. and G.S. Khush, 1987. Genetic analysis of resistance
to green leafhopper, Nephotettix virescens (Distant), in some selected
rice varieties. Crop Protection 6(4): 244-249.
Siwi, B.H. and G.S. Khush, 1977. New gene for resistance
to the green leafhopper in rice. Crop Science 17:
17-20.
|
