Climate change affects staple food crops like sweet potato, but there's limited research on its specific impacts on local varieties in Papua New Guinea's Goroka region, highlighting the need for studies that explore how different kaukau species respond to climate stressors and integrate farmer perspectives in finding resilient varieties.
Literature Review
Global research extensively documents the multifaceted impacts of climate change on staple food crops, with a strong emphasis on cereals and, increasingly, on root crops like sweet (ipomoea batatas). Studies provide broad theoretical frameworks on how altered temperature regimes, erratic rainfall, and increased CO2 levels fundamentally affect crop physiology, including photosynthesis, nutrient uptake, and overall yield potential (Kumar et al., 2024). Specifically for sweet potato, literature from diverse tropical regions highlights observed impacts like reduced tuberization under drought stress, increased susceptibility to pests and diseases due to warmer temperatures, and shifts in optimal growing seasons. These studies often employ methodologies ranging from controlled environment experiments to regional climate modeling, providing a foundational understanding of sweet potato's responses to various climatic stressors, which serves as a theoretical lens for examining the Goroka context (Raymundo et al., 2014).
However, despite this growing global understanding, a significant gap exists concerning the specific impacts of climate change on indigenous or locally adapted kaukau (ipomea batatas) species within the unique agro-ecological zones of Papua New Guinea, particularly the Goroka region. While general climate projections for PNG suggest increased temperatures and altered rainfall patterns, the direct empirical evidence of how these macro-level changes manifest in the physiological responses and productivity of the diverse kaukau varieties cultivated by Gorokan farmers remains largely underexplored (Hickey, 2013). For instance, observations of "bigger, healthier and more productive" kaukau elsewhere in PNG, like the Markham Valley, underscore this critical knowledge gap: what specific environmental factors contribute to such performance, and how do they contrast with changing conditions in Goroka? This study aims to bridge this gap by providing concrete data on species-specific resilience to localized climatic pressures, directly addressing the research questions on how climate change affects kaukau growth, yield, and resilience in Goroka, and identifying particularly vulnerable or resilient species (Daly, 2024).
The empirical literature reviewed highlights a critical need for climate-resilient food systems, particularly for staple crops like sweetpotato, which is the fifth most produced crop globally. Researchers from IRD, CIRAD, and CIP conducted a comprehensive study, published in Nature Climate Change, demonstrating the significant role of intraspecific diversity in sweetpotato for enhancing productivity and resilience against climate change. Their methodology involved screening 1,973 sweetpotato varieties from CIP's genebank, encompassing modern, traditional, and breeding lines from 50 countries(Heider et al., 2020). These were cultivated under controlled irrigation in a Peruvian test site, with repeated exposure to temperatures exceeding 35°C to assess heat stress tolerance. This extensive mass screening, unprecedented in its geographical scope across America, Africa, and Asia, identified 132 heat-tolerant cultivars, with 65.9% being traditional local varieties. This finding underscores the adaptive capacity inherent in traditional landraces, a result of centuries of co-evolution between farmers and their crops, and emphasizes the crucial role of agrobiodiversity in bolstering the resilience of tropical agricultural systems. Furthermore, the study suggests canopy temperature and carotenoid levels as potential markers for selecting heat-tolerant lines, offering avenues for more efficient breeding strategies (Schaeffer et al., 2025).
While the study effectively demonstrates the potential of intraspecific diversity in sweetpotato for climate resilience and identifies promising heat-tolerant varieties, there are clear gaps in the existing knowledge that warrant further investigation. Firstly, the study, while extensive in its screening, was conducted under controlled field conditions in a single geographical location (coastal desert region of north Peru). This raises questions about the generalizability of these findings to diverse agroecological zones and varying farming practices globally. Different soil types, rainfall patterns, pest and disease pressures, and socio-economic contexts could influence the performance of these identified heat-tolerant varieties. Secondly, the research, while suggesting potential markers for selection (canopy temperature and carotenoids), explicitly states that "participatory experiments need to be conducted in different contexts, to test the efficacy and economic viability of the varieties identified." This highlights a significant gap in the literature regarding the practical implementation and adoption of these heat-tolerant varieties by small-scale farmers (Heider et al., 2021). There's a need to understand farmer preferences, market demands, and the socio-economic feasibility of integrating these new varieties into existing farming systems. Future research should therefore focus on participatory on-farm trials across diverse environments and engage directly with farming communities to ensure that scientific findings translate into tangible benefits for climate-vulnerable populations (Wilkus et al., 2017)
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