Nine sweet potato varieties with different flesh colors were cultivated under uniform environmental conditions with potassium (K) fertilizer treatments at levels of 0, 22.5, and 45 kg/ha. The structural and functional properties of the starches were subsequently analyzed. The soluble sugar content in the dry root tuber increased, with higher K levels in most varieties. Amylose content decreased in Sushu16 but increased in Ningzishu1, with no significant differences observed in other varieties across different K levels. Elevated K levels had no effect on starch protein content, crystalline type, or gelatinization enthalpy. The impact of K fertilizer on starch thermal and pasting properties varied among the varieties. PLSR and PLS-DA analyses revealed that genotype background was the primary factor influencing starch properties. This research will provide a reference for the improvement of sweet potato production quality and efficiency and a scientific basis for the cultivation and utilization of sweet potato root tubers.

This study analyzed the genetic progress of sweet potato (Ipomoea batatas) breeding in Cuba over the past 50 years by field trials comparing traditional and improved varieties. Improved varieties significantly outperformed traditional ones in tuberous root yield, with an accumulated genetic gain of 0.20–0.37 t ha⁻¹ per year, translating to a 256% yield increase. Improved genotypes also exhibited enhanced pest tolerance: lower weevil (Cylas formicarius) infestation and reduced nematode (Meloidogyne incognita) reproduction rates. For viral diseases, 60% of improved varieties showed incidence rates below 10%, compared with 90% of traditional varieties exceeding this threshold. Under drought conditions, improved varieties showed tolerance, with Stress Susceptibility Indices (SSIs) of less than 0.8, while the traditional varieties were more susceptible (SSI > 1). Phenotypic stability analysis via GGE biplot confirmed the superior yield and adaptability of improved varieties across environments. These advances underscore the critical role of sweet potatoes breeding in Cuba, with improvements in yield, quality and resistance to biotic and abiotic stress, contributing to strengthening climate resilience and food security.

The sweet potato is a pivotal crop for global food security due to its adaptability and nutritional value. This chapter explores its genetic improvement, spanning reproductive biology to variety development. It addresses the challenges posed by its complex hexaploid genetics and sporophytic self-incompatibility system, which limits inbreeding and enhances genetic diversity. The chapter details the inheritance patterns of traits such as skin color and root shape, which are influenced by polyploidy and environmental effects. Furthermore, it describes advanced methodologies for directed crosses, flowering induction under artificial conditions, and controlled pollination techniques, essential for overcoming reproductive barriers. The chapter also outlines a structured breeding program comprising seven stages: from hybridization and preliminary selection through genotype-by-environment (G × E) interaction studies to variety release. Emphasis is placed on phenotypic stability, pest resistance, and abiotic stress tolerance. Synthesizing technical and practical knowledge, the chapter offers a comprehensive guide for plant breeders and agricultural scientists dedicated to innovating this vital crop.

Sweetpotato (Ipomoea batatas [L.] Lam.) is a vital crop for food security, yet yields in Cuba remain below potential (2.5–10.0 t ha⁻¹) due to suboptimal propagation practices. This study investigated the impact of nodal position (1–22) on root development in stem cuttings of cv. ‘INIVIT B-240’ under controlled conditions. Root primordia (24 h), fibrous roots (7 days), and storage roots (60 days) were evaluated. Intermediate nodes (8–12) exhibited superior rhizogenic capacity, with node 10 showing the highest root primordia density (3.0 ± 3) and nodes 10–12 producing the most fibrous roots (24.6–26.7 roots/cutting). Storage root formation was optimal at nodes 5–13, particularly nodes 8–11 (1.30+ roots/node; highest biomass). Multivariate analysis (Integrated Performance Index) confirmed nodes 8–12 as the most productive cluster. These findings challenge traditional apical-cutting practices, showing that mid-stem nodes optimize both rooting and tuberization. We propose inverted planting of pre-apical sections to bury high-performance nodes, potentially increasing yields in resource-limited systems.

A breeding program was established in Cuba using 19 full-sib families of sweetpotato (Ipomoea batatas [L.] Lam.) introduced as botanical seed from the International Potato Center (CIP). The objective was to develop biofortified cultivars combining high yield, phenotypic stability, and high β-carotene content under tropical conditions. The program followed a four-stage pipeline: (1) F₁ population establishment and visual selection (1732 plants) for morphological and pest/disease resistance traits; (2) initial clonal evaluation (C1) of 103 genotypes, estimation of genetic parameters, and multi-trait selection; (3) advanced evaluation of 19 elite genotypes, including analysis of genetic correlations and stability across two seasons; and (4) multi-environment trials (13 locations) with AMMI, GGE biplot, and MGIDI analyses. General and specific combining abilities were estimated, and broad-sense heritability (H²) was calculated. Three new biofortified cultivars ‘INICIP Dorado-4’, ‘INICIP B-30’, and ‘INICIP B-60’ were selected. These combine high yields, high β-carotene content, and distinct profiles for specific agronomic niches, with a total cumulative phenotypic gain of +352.8% achieved over four selection stages within a three-year period. This pipeline constitutes a replicable model for resource-constrained regions, demonstrating the potential of CIP germplasm to drive sweetpotato biofortification.