Reaction of Peanuts to Dry and Wet Growing Periods in Brazil 1

Reactions of Spanish‐Valencia, Virginia bunch, and runner peanut varieties and strains to wet and dry growing periods were studied during three growing seasons, 1959 to 1962, in the western part of the State of Sao Paulo, Brazil. During the three wet seasons Spanish—Valencia peanuts made better use of excess moisture at high temperatures than did the other two groups. Virginia bunch and runner varieties and strains reacted similarly and rather uniformly within each group during these three growing periods. Excess moisture influenced the development of these two groups negatively. During the dry seasons the productivity of Spanish‐Valencia peanuts was below that of the other two groups when the planting date was early enough to avoid extreme conditions. The Virginia bunch peanuts maintained their wet‐season growing pattern in the dry seasons of 1960 and 1961 with a slight yield advantage for the dry season crops. This peanut group was less affected by either moisture or temperature unless very low rainfall and temperatures exceeded the adaptability of this group. This was demonstrated by experiments made during the dry season of 1962. The runner peanuts fell into two groups on the basis of the dry season experiments, one group reacting like Spanish—Valencia peanuts, the other like Virginia bunch peanuts. Genetical background and a higher sensitivity to temperature differences were suggested as the main causes for this reaction pattern.