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Wheat Information
Service
Number 72: 12-13 (1991)
Use of
weak-necrotic mutant variety PNC 306 to preclude hybrid lethality in
wheat crosses
0. P. Srivastava
Indian Agricultural Research Institute Regional Station, Pusa,
Bihar 848125, India
Hybrid lethality reported in F1's is one of the major
barriers (Pandey and Rao 1979) encountered by many wheat breeders for
combining desirable genes from different varieties into hybrid
combinations. Some of the promising indigenous varieties like C286,
C306, NP839 have been found to produce strong lethality in crosses
with the Mexican Ne2s carriers, Sonalika, Chotti
Lerma, Safed Lerma and Kalyansona (Narula et al 1970; Gill et al
1969, 1972; Anand et al 1969; Kochumadhavan et al 1980). As a
consequence of hybrid lethality many F1's die at
prematurity, imposing a serious limitation on the choice of desirable
recombinants. The present paper reports the results to elicit
informations for the use of weak-necrotic mutant variety, PNC 306,
for obtaining desired combinations with Ne2s
carriers.
Three varieties, S 308, Kalyansona and HP 1303, all
Ne2s carriers, were crossed with a mutated
variety PNC 306. The parents, S 308, Kalyansona, HP 1303 and PNC 306
as well as the F1 plants by the crosses of S 308,
Kalyansona and HP 1303 with PNC 306 were space-planted in the field
along with the F1's
seeds of S 308,
Kalyansona and HP1303 with C 306 as control during the rabi
season 1982-83. A variety C 306 is a carrier of
Ne1s.
It is apparent from the results that all the
F1's, S
308 x PNC 306, Kalyansona x PNC 306 and HP 1303 x PNC 306 grew
normally and reached full maturity (Table
1), whereas
F1's of the control crosses of S 308, Kalyansona and HP
1303 with C 306, died at 2-3 leaf seedling stage without forming ears
and seeds. The hybrid nature of the F1 plants was
identified by glume pubescence. The stem length of normal
F1's ranged from 72.0 to 78.6cm with normal leaf sector
extending upto the flag leaf stage which had normal head and varying
degree of seed setting. The seed was quite normal, with thousand
grain weight ranging from 40.6 to 45.6g. The number of ears per plant
ranged from 9.0 to 10.6 with good seed set and a fairly large
quantity of F2 seeds was obtained from these plants. The
F1 plants showed slight yellowing of leaves and manifested
low degrees of necrosis (grade, 0-1), as suggested by Hermsen (1963).
The result suggests that the variety PNC 306 carried a weaker allele
of Ne1. As it is suggested from the results in
Table1
that the Ne1s (strong) dominant allele
present in the variety C 306 has been mutated to a weaker allele in
the variety PNC 306 as it is not a completely effective non- carrier
in crosses with Ne2s carriers. Similarly.
Pukhalskii (1972) showed that the durum wheat mutants Senator Sr Sv
2, Sr 48, Sr V 132, Sr V 144 which were obtained by irradiation with
neutron and x-rays were ineffective for the preclusion of
Ne1s gene for hybrid necrosis.
Induction of weak or non-necrotic mutation in carriers of strong
necrotic alleles with the desirable characteristics is important if
breeders are to utilize them frequently in crossing programme.
Preclusion of hybrid necrosis might be possible by using
weak-necrotic mutant variety PNC 306.
The author wishes to express his sincere gratitude to Dr. M. V. Rao,
IARI, New Delhi for supplying the seeds of wheat strain PNC 306 used
in the present study.
References
Anand SC, Gill BS and Jain RP (1969) Necrosis in intervarietal
crosses of wheat. Indian J Genet 29 (1): 131-134.
Gill KSG, Singh B and Gupta ML (1969) Necrosis in hybrids of Punjab
variety of C 306 and Mexican varieties of wheat. PAU J Res 6:
10-13.
Gill KSG, Singh B and Gupta ML (1972) Genetics and developmental
analysis of hybrid necrosis in wheat. Indian J Genet 32: 12-17.
Hermsen JGTh (1963) Hybrid necrosis as a problem for the wheat
breeder. Euphytica 12: 1-15.
Kochumadhavan K, Tomar SMS and Nambisan PNN (1980) Investigations of
hybrid necrosis in wheat. Indian J Genet 40: 496-502.
Narula PN and Srivastava OP (1970) Effect of gamma rays on the
expression of hybrid necrosis in wheat. Wheat Inf Serv 31: 13-15.
Pukhalaskii VA (1972) A study of some durum wheat mutants for the
presence in their genotypes of genes for hybrid necrosis. Dokl.
ISKHA. 187: 73-74. Plant Breed Abstr 44 (1974) No. 4262.
Pandey HN and Rao MV (1979) Hybrid necrosis in Indian Durum wheats.
Indian J Genet 39: 444-445.
Zeven AC (1965) First supplementary list of genotypes of hybrid
necrosis in wheat varieties. Euphytica 14: 239-243.
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