Morphological variation of starch granules in S1 cassava progenies

The need to develop new cassava ( Manihot esculenta Crantz) varieties with different starch characteristics has greatly motivated new research. The aim of this study was to evaluate morphological alterations in starch granules as well as genetic gains in segregating S 1 cassava populations. Starch from accessions (S 0 ): BGM0222, BGM1378 and BGM1662 and from their self-fertilized progenies (S 1 ): F0222, F1378 and F1662, with 78, 80 and 76 individuals, respectively, were evaluated for the following traits: area (ArStGr, µm 2 ), perimeter (PrStGr, µm), length (LeStGr, µm) and number of starch granules (NuStGr). Moreover, some agronomic traits of the S 1 progenies were evaluated at harvest such as: plant height (PlaHei), shoot yield (ShoYi), root yield (RoYi), starch yield (StYi), and root dry matter content (DMC). With the selection of transgressive individuals in S 1 progenies, it is possible to obtain selection gains for values higher and lower than the average of the S 0 genitors, whereas selection gains can reach up to 16.58, 8.39, 7.87 and 34.18% for ArStGr, LeStGr, PrStGr, and NuStGr, respectively. Average size of the starch granule varied from 9.8 to 12.37 µm among individuals in an S 1 progeny. Positive and high correlations between the individuals were found for some morphological characteristics of the cassava starch granule but not strongly correlated with agronomic traits. Therefore, it is possible to select S 1 cassava individuals for agronomic characteristics without losing other important starch traits. Cassava-segregating populations allow the obtainment of individuals with different morphological characteristics as for starch granules, enabling obtainment of genetic gains with the selection.