Title: INDUCTION OF MUTATIONS FOR RUST RESISTANCE IN WHEAT

Abstract

To test the possibility of artificially inducing resistance to rust in a susceptible wheat and to ascertain whether the dominance or recessiveness of the resistant reaction influences in any way the observed result, M/sub 2/ and M/sub 3/ progenies of the bread wheat variety C 591 treated with different mutagens were screened for resistance to races 21, 40, and 42 of stem rust. C 591 is a fully awned spring wheat characterized by a good quality of grain but high susceptibility to rusts. Seeds were collected from M/sub 1/ plants after the following treatments: 11000 and 16000 r of x rays; fast neutrons given for 3.5 and 8 hr at a flux of 10/sup 9/N/cm/sup 2//sec; thermal neutrons given for 41.4 min at a flux of 8 x 10/sup 9/N/cm/sup 2//sec; and P/sup 32/ applied to pots at 25 and 50 mu c per plant. In the M/sub 2/ population tested, no seedling with a reaction to rust different from that shown by the controls was observed. Some of the progenies of treated plants segregated for albinos. No infection was observed in the albino mutants, though repeated inoculations were carried out and the albinos survived for a period longer thanmore » the incubation time required by the pathogen (i.e., about 10 days after inoculation). Some M/sub 2/ plants belonging to families treated with 16000 r of x rays were fairly free of rust irfection, so 5 such plants were bagged and seeds were collected from each of them separately. When the M/sub 3/ progenies raised from them were tested for resistance in the seedling state to races 15c, 24 and 40 of stem rust, it was found that one family was immune to race 40 (0 type of infection). About 100 plants of each of these families were raised and shown to be uniform in morphologic characters and resemble the parent strain in all respects except in the color of glumes and rust resistance. The close similarity between the mutant and the parent variety in plant habit, maturity, grain quality, ear, and awn characters, as well as its true breeding nature, indicates that it could not have arisen through chance out- crossing. This mutant had brown glumes in contrast to the white glumes of the parent strain. The susceptibility of C 591 to race 40 of stem rust appears as a recessive character in crosses with resistant varieties. The mutation conferring resistance should hence be technically regarded as belonging to the rare class of dominant mutations. In bread wheat, however, it is difficult to establish dominance relations for many loci accurately, hence it would be premature to classify the mutant as a dominant one. No other mutant was found after the radiation treatments, although albino seedlings were totally free of rust infection. It is concluded that mutations for rust resistance can be induced in bread wheat by ionizing radiation but that the frequency of such mutations is very low, occurring only in a few of the 25,000 seedlings tested. (BBB)« less

Authors:

Bhatia, C; Swaminathan, M S; Gupta, N

Publication Date:

Sun Jan 01 00:00:00 EST 1961

Research Org.:

Indian Agricultural Research Inst., New Delhi

Sponsoring Org.:

USDOE

OSTI Identifier:

4631531

NSA Number:

NSA-17-039362

Resource Type:

Journal Article

Journal Name:

Euphytica. Netherlands Journal of Plant Breeding (Netherlands)

Additional Journal Information:

Journal Volume: Vol: 10; Other Information: Orig. Receipt Date: 31-DEC-63

Country of Publication:

Country unknown/Code not available

Language:

English

Subject:

INDUSTRIAL APPLICATIONS OF ISOTOPES AND RADIATIONS; CEREALS; COLOR; INFECTIONS; IRON OXIDES; IRRADIATION; PARASITES; PHOSPHORUS 32; RADIATION EFFECTS; RUST; SEEDS; STABILITY; THERMAL NEUTRONS; X RADIATION