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, chefes de estações experimentais onde foram realizados os ensaios. Agradece também os trabalhos do Sr. José Francisco, auxiliar de agrô-nomo, da Secção de Raízes e Tubérculos.

As mutações somáticas que ocorrem nas variedades econômicas de batata doce podem apresentar características vantajosas, passando a constituir novos tipos comerciais, utilizados com finalidades diversas. No decorrer dos trabalhos em realização na Secção de Raízes e Tubérculos deste Instituto, sôbre vários aspectos agronômicos e sôbre o melhoramento da batata doce, foram observadas seis mutações somáticas, tôdas elas afetando principalmente a coloração das raízes. A descrição dessas mutações e o seu valor econômico são mencionados. Na variedade 98-Castelo, a mutação afetou a côr da periderme que, de roxo, passou para creme, enquanto na variedade 18-Viçosa (Dahomey), a mudança de côr se deu na periderme e córtex que, ao mesmo tempo, de roxo mudaram para roxo-avermelhado e creme, respectivamente. Na variedade 39-Roxa pilosa, a periderme roxo-escura se tornou côr de cobre e o córtex e o cilindro central de roxo-escuro se tornaram creme. Na variedade 104-Peçanha rosa, a alteração ocorreu na periderme, que passou de rosa-pardo a vermelho-arroxeada. No "seedling" 104 S50-6, a periderme roxo-escura se tornou creme, enquanto no "seedling" 113 S50-11 a periderme amarelada mudou para lilás e o córtex e cilindro central, de amarelados, passaram a ter a côr roxa. Chamou-se atenção para a combinação de côres encontrada nesta última mutação, ainda não observada em Campinas. Apenas as duas primeiras mutações foram estudadas quanto à produção. Verificou-se, neste particular, que se assemelham às variedades originais, as quais são das mais recomendáveis para a agricultura de São Paulo. Ambas, porém, apresentam a vantagem de possuir a casca mais clara, o que melhora sua aceitação no mercado.
During these last 5 years six somatic mutations were found in commercial varieties of sweet potatoes grown in experimental fields of the Roots and Tubers Dept. of the Insiitvto Agronômico de Campinas. All these mutations affected the color of various root layers and their descriptions are presented in this paper. In variety 98-Caslelo the purple periderm became cream in the mutated form while in the variety 18-Dahomey the purple color of periderm and cortex have been changed to purple-reddish and cream respectively. The mutation in var. 39-Roxa pilosa affected the periderm color, which changed from dark-purple to light copper and the cortex and central cylinder from dark-purple to cream color. In the variety 104-Peçanha rosa which possesses a rose-brown periderm the mutation produced a red-purplish periderm. In the seedling 104-S50-6 the dark-purple periderm became cream while in the mutated form of the 113 S50-11 seedling the yellowish periderm was changed to light-purple and the yellow cortex and central cylinder became purple. Attention has been called to the root flesh color of the seedling 113 S50-11 which is unique in the collection of sweet potatoes types at Campinas. Only the mutations that ocurred in varieties 98-Castelo and 18-Dahomey have been tested for yield dining these last two years. It has been found that both new types are s...

This paper reports a preliminary study of four sweet potato varieties, Russia, Napoleão, Roxa and Viçosa, carried cut in 1939-40 at the Central Experiment Station, Instituto Agronomico. Comparative plots of each variety were harvested after 3, 4, 5, 6, 7, 8 and 9 months of vegetation, the product being then examined for the following characters : a) Total yield b) Number of roots c) Average weight of the potates d) Production of different grades e) Qualities of the fresh roots f) Culinary value of the sweets potatoes The yield after three months of vegetation was very small for the four varieties, but increased considerably in the later harvests. The variety Napoleão attained its highest yield after six months, being early; Roxa yielded most after seven months, being medium early, and the varieties Russia and Viçosa were late, giving their maximum yield only after eight months. The last named variety, in spite of occupying third and fourth position as regard to yield up to the fifth harvest (seven months), exceeded greatly the others at the eight and nine month harvests. The number and average weight of rcots varied according to the variety, and influenced the yield in different ways. The increase in yield of the variety Roxa resulted from an increase in the number of rcots, the average weight of these remaining practically the same at the various harvests. The var. Napoleão, on the other hand, increased in yield as a result of an increase in the weight of the rcots, the number of these not varying significantly at the success ve harvests. Both factors influenced the yield of the var. Russia and Viçosa, especially the increase in weight of the roots. Grading ihe product in six different sizes showed that the yield of the var. Roxa is predominantly of small sized sweet potatc es ; the var. Russia has medium roots. Napoleão has large rcots and Viçosa, very large ones. Other characters of the roots as shape, color, etc., were also studied, and culinary te sts were made with fresh sweet potatoes and with roots that had been cured under the sun

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