Benefits of improved taro varieties

Taro seed garden at MRC for multiplication
Jeffrey Waki

Over the past two decades the PNG National Agricultural Research Institute (NARI) has conducted research to develop new innovations to improve agricultural knowledge and practices in the smallholder sector. Such efforts have led to many useful technologies being released especially in regards to generating improved varieties of important food crops. One crop in which much work has been done on is taro. Taro is a traditional staple crop that is cultivated from sea level up to 2400m altitude and is the third most consumed after sweet potato and banana. Apart from being primarily used as food, taro also has great customary value among diverse cultures throughout PNG.

The need for research into taro came about when Taro Leaf Blight (TLB) devastated the domestic and export earnings of smaller Pacific island countries and territories (PICTs) like Samoa, in the 1990s. TLB is a very destructive disease caused by a fungal organism which affects taro leaves, The organism could be spread from infected plants by wind-driven rain and dew to nearby taro plants and gardens.  Initial signs of the disease are small brown water-soaked spots on a leaf that would enlarge and turn dark-brown as the disease spreads. Secondary infections would then set in and cause a leaf to die rapidly within a period of three weeks or less. The disease could reduce the number of functional leaves significantly resulting in as much as 50% loss in crop yields.

Carrying on from initial efforts by the Department of Agriculture and Livestock, the institute has developed improved varieties of taro with the support from Australian Aid (now Department of Foreign Affairs and Trade) and European Union Aid programmes. To date, eight NARI Taro (NT) varieties have been bred, evaluated and released. These varieties contribute to socio-economic as well as nutritional benefits for smallholder farmers.

NTs are improved hybrid varieties which had been selected through conventional breeding and evaluation processes. The breeding approach involved assembling a set of different taro varieties with unique but desired characteristics such as TLB tolerance and good eating quality. From these collection, new varieties were developed through the process of hybridization where different taro varieties were crossed (or mated). The developing seeds were then harvested and evaluated over time in several cycles. First four varieties were released in 2003 while the next batch was launched recently in 2017. Two of these varieties were adopted from a Samoan breeding programme and have adapted well to our climate and soil conditions.

One of the main advantages of these varieties is the high level of resistance to the important TLB disease and varieties have shown high adaptability across different agro-ecological environments. This is particularly significant in light of increased prevalence of extreme climatic events. The taste and eating quality of NTs are comparable to local varieties. However, with an average yield of about 10 tonnes per hectare - without use of external inputs – NT outputs could be two or three times higher. NTs mature in about the same time as both lowland and highland varieties in six and 10 months, respectively.

These qualities make it viable for farmers to apply post-harvest processes to add nutritional and commercial values to NT produces. Popular products that smallholder farmers could make out of NT corms include taro chips, mashed servings and taro flour. There is also potential to create taro flakes, taro cakes and taro ice creams. These together with raw taros could be packaged to target different segments of the informal and formal fresh produce markets, at very competitive prices. For example, a kilogram of fresh corms could fetch up to K10 at supermarkets.

NT varieties can also provide useful nutritional and health benefits. Their corms, especially the yellow-fleshed type, have low levels of calories but higher beta-carotene content. The leaves are also good sources of vitamins A and C. These qualities can enhance the body’s defenses against diseases of the heart as well as various forms of diabetes and cancer.

Additionally, NT varieties promote environmentally friendly farming practices in that dependence on chemical controls for diseases like TLB is very minimal to none. This greatly reduces risks of ecosystem destruction from uncontained pesticide run-offs and spillages. Furthermore, NTs can be planted to diversity the range of varieties grown in gardens. This is important because in the event that certain varieties fail, those that prevail would continue to sustain good levels of food security.

Taro is one of the important focus crops for research in NARI. It makes every effort to promote NT varieties to smallholder farmers during its field day exhibitions, annual innovation shows and provincial agricultural shows there is great potential for downstream processing and industrial product development.