Germplasm diversity in cassava collections for special traits

Cassava is considered a staple for million of people in marginalized regions of the world. It is an important crop in the global market and is one of the most significant root crops in area and production in the Philippines. Germplasm conservation and assessment of the morphological diversity of the collections are important in the preliminary selection and breeding of cassava to identify accessions with special traits. The purpose of this study is to characterize, access the diversity and identify accessions with special traits of cassava. Fifty-six accessions were planted in 2018 at the experimental field D1-East Tranca of IPB, UPLB [Inst. of Plant Breeding, University of the Philippines Los Baños, Laguna, Philippines] for morphological characterization and chemical evaluation. Data for 34 parameters including plant body and root data descriptors and measurements were taken 9 months after planting. Analysis of data collected revealed high diversity indexes with the highest ones being the parameters prominence of leaf scars (H = 0.94), plant form (H1 = 0.93), and ease of root cortex peeling (H1 = 0.98). Storage root traits indicative of yield, such as of storage roots per plant (H1 = 0.81) and fresh weight of storage roots (H1=0.79) also showed high diversity. Analysis of nutraceutical properties of storage roots of 48 identified promising accessions with high starch (85.13%-90.99%) and energy contents (379.92 kcal/100g-417.65 kcal/100g), superior protein (0.96%-1.80%) and low hydrogen cyanide content (8.12ppm-164.93ppm: anti-nutrient). Considering the selection criteria of the plant breeders such as erect, non-branching growth habit, high fresh root yield, high values of root dry matter, starch content and root carotenoid, low root HCN, 27 accessions were selected as very promising. This wide genetic variability in the germplasm collection of cassava is important in developing superior varieties with special traits.