Cajanus scarabaeoides

Cajanus scarabaeoides is a flowering plant in the genus Cajanus Of the 32 different species within the genus Cajanus, only one, C. cajan (pigeonpea), is cultivated. Cajanus scarabaeoides is the closest wild relative to C. cajan, and is one of the easiest wild species to cross with pigeonpea cultivars. C. scarabaeoides is found naturally in both temperate and tropical zones around the globe. This species has higher levels of drought tolerance, is found to have greater protein content, and has higher levels of resistance to insect pests compared to cultivated types. These genetic traits can be crossed with C. cajan to improve the crop’s productivity. For subsistence farmers, this can reduce economic losses and drastically improve overall crop yield. Cajanus scarabaeoides is a very close wild relative species of Cajanus cajan (common name, pigeonpea). It is a dicot angiosperm belonging to the Fabaceae family. C. scarabaeoidis may be an annual or a perennial, making it a flexible crop for subsistence farmers. The branches of C. scarabaeoides can be straight or winding and up to 135 cm in length. C. scarabaeoides has pinnate leaves, typically arranged in a trifoliate manner with flowers that are yellow with red veins. The pods of C. scarabaeoides are oblong in shape, typically 11–34 mm in length and 6–10 mm in width. The seedpods are densely covered in a combination of short and long hairs and are typically a dark purple colour, containing anywhere from 1-7 seeds. The seeds of C. scarabaeoides range from 2.4–4 mm long, 1.8–3 mm wide, and 1–2 mm thick and are either black in colour or speckled. Compared to the pigeonpea cultivars, C. scarabaeoides has a higher pod seed percentage, 74% compared to 20%, and has more multiseed pods, on average 6.04 seeds compared to 3.0 seeds C. scarabaeoides is the most widely distributed wild species of C. cajan and is native to many countries in both temperate and tropical zones. It is native to Madagascar in Africa. In temperate Asia it is native to China, Japan and Taiwan. In tropical Asia it is native to Bangladesh, Bhutan, India, Nepal, Pakistan, Sri Lanka, Myanmar, Thailand, Vietnam, Indonesia, Malaysia, Papua New Guinea and the Philippines. In Oceania it is native to Australia and Fiji. In Asia, C. scarabaeoides is the most commonly disbursed wild species and can be found in abundance in the Chinese provinces of Yunnan, Guizhou, Guangxim Guangdong, Hainan, Fuijan and Taiwan. In China there are several other names for this species. In Mandarin Chinese it is called “Man Cao Chong Duo”. In Guangdong dialect it is called “Shui Kom Ts’o”. In Yunnan dialect it is called “Jia Yan Pi Guo”. C. scarabaeoides occurs naturally in the wild, and can be found in open grassland and dry vegetation areas and in deciduous forests. It is often found along the ridges of cultivated fields, along roads or footpaths, or on hill slopes. It is typically found where there is a decent amount of sunlight, and populations tend to dwindle in dark bush areas or dense forests. This crop is known as a “creeper-climber” that supports itself on surrounding grass and small shrubs. In the Tiandong county in the Guangxi province of China, it can be found growing in wastelands at elevations of 180 m. In the Yi Oun Yang mountains, it can be found growing wildly in the dry hills and beside rivers. The vast areas in which this crop has the ability to grow provides advantages for farmers in both rural and peri-urban areas, as it can be supported by a variety of environments. While pigeonpea is already a particularly good crop in terms of resistance to drought, C. scarabaeoides has even greater drought tolerance properties and is therefore capable of thriving with very little annual rainfall. In many accessions studied of C. scarabaeoides, many have been found to flower early compared to pigeonpea cultivars. One ICRISAT study reports flowering in some C. scarabaeoides accessions as early as 34 days compared to 60 days and another ICRISAT study reports C. scarabaeoides accessions flowering within 70 days compared to 126 days. If C. scarabaeoides can be crossed with pigeonpea cultivars for this desirable trait, farmers can reduce harvest time and increase overall yield. With the world’s changing climate, this trait is useful to improve the long-term sustainability of the pigeonpea crop