[en] Published in summary form only. 9 refs

[en] The most important results of cereal mutation breeding are presented as examples of the usefulness of techniques for crop improvement. These economically valuable results were obtained with very limited input. It was demonstrated that the mutation method, in comparison to conventional plant breeding, involved only a small number of breeders with limited facilities and financial support. The introduction of biotechnology methods in plant breeding provided an opportunity for wider implementation of mutants and mutation techniques. (author). 33 refs, 4 figs, 1 tab

[en] Dry seeds of the cultivar Intan from Karnataka, India were treated with ethyleneimine at 0.2% and 0.4% concentrations for 1 hour and 3 hours to induce early maturity without affecting resistance to blast and ratoonability. The germination percentage with seeds and spikelet fertility in M₁ plants showed correlation and was useful in identifying optimal treatment for future experiments. Single panicles selected from the treatment 0.4%-3 hours produced progenies for further screening. Screening of M₂ families in natural long day length in the 1979 dry season facilitated selection of early maturing photo-period insensitive types from Intan mutations (IR 29385). The early maturing mutants grown in the wet season as M₃ plant progenies, bred true for earliness, matured about 20 days earlier than the parents, even with short day length. Mutants had reduced plant height with not much change in panicle length, grain features, spikelet number and fertility with panicle. Among the mutants selected, Intan mutant 1 performed very well under subnormal and normal fertilizer application. It yielded 1.10% higher than the checks and parent variety in addition to being itself early by about 20 days. If ethyleneimine is specific in altering culm length, it should be emphasized as a future tool in the improvement of specifically adapted traditional varieties. (author)

[en] Published in summary form only

[en] Eight cultivars that were thought to have field resistance to stem rust were selected and crossed to produce four four-cultivar hybrids. From those crosses lines were produced that lacked seedling resistance to race 15B-1 of stem rust but had good field resistance to it. They also proved to have field resistance to many other races and it is hoped that the resistance is general. Genetic studies indicated that there is some variation in the lines, but resistance is generally inherited as a quantitative character with several largely recessive genes having small additive effects. This suggests that in an induced mutation programme, no one plant is likely to accumulate sufficient mutant genes that it will appear resistant. (author)

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[en] A series of families selected from the progeny of rice of the Arlesienne variety - from the National Institute for Agricultural Research (INRA) - after mutagenic treatment was studied with regard to their reaction to artificial infection by two types of pathogenic cryptogam which are found in France and which cause sclerotial diseases in rice. The mutagenic treatment was carried out in 1970, at the Montpellier Plant Improvement Station, with gamma rays from a cobalt source provided by the French Commissariat a l'energie atomique. The aim was to improve the Arlesienne variety, which, although of excellent quality for culinary purposes, was difficult to thresh (excessive resistance to extraction of kernels from husks) and to handle in the mill (pronounced villosity). Screening, done in 1971, and consecutive selection produced mutants which did not entail these difficulties; 28 families (M₆ in 1975) were finally chosen for their superiority to the control. The Plant Biology and Pathology Laboratory at Montpellier has analysed the extent to which these mutants would be resistant in the event of an epidemic of Sclerotium. Eight families exhibited low or very low overall susceptibility to S. oryzae, 21 to S. hydrophilum and seven to both at once. From the practical point of view, four families are clearly superior to the Arlesienne control, one of them possessing great agronomic value. Several families proved to be less resistant than the parent variety, which confirms the mutation direction symmetry rule. (author)

[en] A field experiment has been carried out to evaluate the residual effect of zinc fertilizers by rice plant grown under flooded conditions in the field. The results obtained are summarized as follows: Residual effect of zinc fertilizers on yields of rough and hulled grains showed slight increases. Effect of zinc application methods on yields of the grains were shown that zinc mixed treatment could be more effectively utilized than treatment of zinc on the soil surface. In case of levels of zinc application, 5kg zinc per hectare represented high yields of the grains than those obtained from 10 kg and 20 kg zinc placement per hectare respectively. Regarding the form of zinc fertilizers, the urea-zinc complex showed less effective on yields of the grains than did the zinc sulfate. This phenomenon was consistent with the previous result. Yields of total zinc in rice plant grown on the rice straw added soils (Treatment No. 2 and 8) and the urea-zinc complex treated soil were increased markedly as compared to those data obtained from the previous year. The percentage of zinc derived from fertilizer decreased largely as compared to that of the first year crop. The yield of fertilizer zinc in rice plant decreased slightly in the most zinc treatments but in the case of treatments of zinc mixed with the straw added soil and the urea-zinc complex increased reversely as compared to the previous results. The mixed application of zinc with soil showed higher yield of fertilizer zinc than the soil surface placement. Approximately from 4.6 to 24.3 per cent of zinc taken up by rice plants were derived from the fertilizer zinc. Zinc fertilizer use efficiency ranged from 0.213 to 0.584 per cent when 5 kg zinc per hectare applied. (author)