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Total sugars, reducing sugars, and phenols were estimated in internodes of tolerant and highly susceptible sovhum genotypes to charcoal, ln tolerant genotypes the sugar level was 2 to 3 times higher than in susceptible ones; phenol concentration also was higher in tolerant genotypes. In tolerant genotypes, sugar and phenol concentration was high in the lower most and in the upper most mternode. This may be used to identify sources of resistance.

Four mutant grou~ldnuts, Arnchis kypognen L., carrying aneuploid chromosomes were isolated. ilteiotic anomalies such as univalent formation, lagging and abnormal distribution of chromosomes were common t o all. Cytornixis was observed in t w o of the mutants and these were sterilc. T h e meiotic anomalies, howcver, did not affect the pollen fertility appreciably.T h e mutants were conspicuous by their largc inflorescences. Their reduced vigor suggests that thc addition of chromosomc(s) excrts a deleterious effect.T h e extra chromosome in a fertile trison~ic mutant carried the mutant characteristic and hence \\>as easily identified in thc segregating progenies. IntroductionT h e change of chromosome number within the species, Itnown as aneuploidy, is useful in breeding crop plants. Experiments in bread wheat (Sears, 1954) demo~lstrate the possibility of transferring beneficial chromosomes from comparatively less useful types via a~leuploids. Breeding for aneuploids with a view to identifying chromosonics and linkage groups has also been reported in other crops such as barley (Hacker and Rilev, 1965) and in tomato, tobacco and cottoll.T h e occurrence of aneuploidv was reported in groundnut by Husted (1936) and Icumar and D'Cruz (1957). The present studies concern the aneuploids obtained from progenies of X-irradiated seeds. Thev include plants with one as well as t\rro additional chromosomes.

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