Browsing by Author "Sanga, Hilda G."

Now showing 1 - 2 of 2

Derivation of seed viability constants (KE and CW) and prediction of seed longevity for spider plant (Cleome gynandra)
(Seed Science and Technology, 2026) Kaweya, Baraka S.; N’Danikou, Sognigbé; Shango, Abdul J.; Sanga, Hilda G.; Kabululu, Mujuni S.; Hamisy, William; Tryphone, George M.; Zonneveld, Maarten van
Amid environmental challenges and the need for global food security, preserving and using plant genetic resources is vital. The expanded seed viability equation predicts longevity under varying storage conditions using species specific constants. While temperature-related constants (CH and CQ) are universally applicable across species, those related to seed moisture (CW) and inherent longevity (KE) vary by species and must be determined individually for accurate predictions. This study used spider plant (Cleome gynandra) to determine viability constants and establish seed longevity under genebank dry storage conditions. The seeds were subjected to experimental storage at 45°C and varied seed moisture contents (7.3, 11.7, 12.8, 14.2 and 15.3%) for 125 days to generate survival curves and hence, KE and CW: 7.656 and 3.55, respectively. The validation of these constants demonstrates their effectiveness in predicting seed longevity for other lots within the same species, showing no significant intraspecific variation. This study provides seed custodians and technologists with a reliable framework to accurately estimate the longevity of spider plant seeds under cold dry storage conditions using the viability equation and the constants derived herein.
Floods stress in lowland rice production: experiences of rice farmers in Kilombero and Lower-Rufiji floodplains, Tanzania
(Frontiers Media SA, 2023-11-30) Michael, Paulo Sulle; Mwakyusa, Lupakisyo; Sanga, Hilda G.; Shitindi, Mawazo J.; Kwaslema, Damiano R.; Herzog, Max; Meliyo, Joel L .; Massawe, Boniface H. J.
The resilience of rice production to floods is a crucial aspect of agricultural development in flood-prone regions. However, little is known about the farming practices and challenges of rice farmers in two river basins in Tanzania: Lower-Rufiji and Kilombero, where rice is the main crop grown. This study aimed to investigate the experiences of farmers in these two rice-growing floodplains regarding the impact of floods on lowland rice production and farmer livelihoods, and the strategies they use to cope with floods. The study used a mixed-methods approach that involved household surveys, key informant interviews, and transect walks to collect data from 180 rice farmers and 14 experts and community leaders. The data analysis revealed that floods were the dominant stressor affecting rice production, occurring mostly during the long rainy season and experienced by all farmers in both locations. Floods not only caused significant crop losses, especially in Lower-Rufiji where farmers reported losing between 75 and 100% of their yield in cases of extreme floods, but also made it difficult to establish and manage crops, leading to crop land abandonment. Floods also affected the livelihoods of rice farmers by forcing them to abandon, rent, or sell their farms. Coexistence of floods with other biotic and abiotic stresses such as crop diseases and droughts also limited the use of short maturing high yielding rice varieties. Farmers have adopted on-farm strategies such as adjusting planting schedules, using different varieties of rice, changing to other crops or activities after the floods to cope with floods, but these practices face numerous challenges. The study recommends the development of early warning systems, breeding for flood-tolerant rice varieties, introgression of tolerance traits to multiple stresses and improving crop establishment methods to enhance the resilience of farmers to floods and other extreme climate events.