Cowpea and other Vigna species in Serbia

Aleksandar Mikić (aleksandar.mikich@gmail.com), Mirjana Milošević, Vojislav Mihailović, Charassri Nualsri, Dušan Milošević, Mirjana Vasić, and Dušica Delić

A cowpea accession in the field evaluation of forage yields in Novi Sad, Serbia. Photo by A. Mikic.
A cowpea accession in the field evaluation of forage yields in Novi Sad, Serbia. Photo by A. Mikic.

Serbia and other countries of the northern and western parts of the Balkan Peninsula have a typical temperate continental climate. The most important grain legume crop here is soybean (Glycine max (L.) Merr.) with an advanced native breeding program carried out in the Institute of Field and Vegetable Crops in Novi Sad. The most widely used pulse is the Phaseolus bean that has almost completely replaced traditional varieties, such as faba bean (Vicia faba L.) or lentil (Lens culinaris Medik.). The pea crop (Pisum sativum L.) retained its place both for human consumption and in animal feeding. Vetches (Vicia spp.) are used as both a forage and green manure crop.

Cowpea (Vigna unguiculata (L.) Walp.) is not completely unknown in the Balkans, with several Serbian/ Croatian words denoting this crop. Often it is called simply vigna, as the whole genus, or prava vigna (true vigna), to distinguish it from the other related species. There are also descriptive names, such as crnookica (black-eyed one) and kravlji pasulj (cow bean). Another name, mletački grašak (Venice pea) suggests that this species was most likely introduced into the Balkans from northern Italy.

Cowpea was distributed in the coastal regions of Croatia, one of the countries that formed the former Yugoslavia, where the Italian cultivar “Cremonese” showed very good results when grown both as a pure stand and in mixtures with Sudan grass, sorghum, and maize.

Today, cowpea has remained a rather neglected and underutilized crop in Serbian agriculture. Only one cowpea cultivar named “Domaća”, of uncertain origin, was included in the official Serbian cultivar list. Cowpea may be found, rather sporadically, along with various market classes of common bean (Phaseolus vulgaris L.), especially in the valley of the Morava river in central Serbia. Local people usually refer to it as pasuljica (little common bean), not really distinguishing it from various types of common bean. Like these, cowpea is used as a vegetable in diverse forms and is grown mainly in gardens.

Recently, along with the introduction of new trends such as the preference for healthy food, it is possible to buy adzuki bean (Vigna angularis (Willd.) Ohwi & H. Ohashi), mung bean (Vigna radiata (L.) R. Wilczek), and black gram (Vigna mungo (L.) Hepper), mostly of Chinese origin. These are used as pulses.

The genetic resources of cowpea and other Vigna species in Serbia are maintained mainly in the Institute of Field and Vegetable Crops, with its Vegetable Crops and Forage Crops Departments, as well as in the Institute of Soil Science, with a total of some 30 diverse accessions.

Since 2004, an evaluation of the most important agronomic traits in cowpea and other Vigna species has been initiated within the field trials in the Institute of Field and Vegetable Crops, at 45°20′ N, 19°51′ E and 84 m asl. As typical warm-season annual legumes, cowpea and other Vigna species were sown in late April. The preliminary results of the trial with cowpea grown for grain were presented at the 4th World Cowpea Congress in Durban in 2005 (Table 1). The most important conclusion from this evaluation was that the short day length in some accessions was the major reason for their inability to produce seeds before the first winter frosts in October.

The next step in testing cowpea potential in the conditions of Serbia was to evaluate its forage yields. It is possible to select the lines that could be developed into proper dual-purpose cultivars, with reliable yields of both grain and forage (Table 2).

table_1

table_2

The evaluation of the cowpea accessions continues along with the evaluation of the adzuki and mung bean that has also brought promising results.

Due to its multipurpose nature, cowpea could be reintroduced into the agriculture of Serbia and other southeast European regions in several ways. An improvement could be made by developing vegetable cultivars for both garden use, with a longer growing period and prolonged maturity, and field production, with prominent earliness and uniform maturity.

An intercropping of mung bean with soybean for forage production, Belgrade, Serbia. Photo by A. Mikic.
An intercropping of mung bean with soybean for forage production, Belgrade, Serbia. Photo by A. Mikic.

As a forage crop, cowpea may play a very important role in providing farmers with fresh forage during the summer months, when the pea crop or vetches have long gone from the fields. However, breeding cowpea for forage production must provide not only good, high quality forage yields, but also reliable seed yields, enabling a newly-developed forage cowpea cultivar to survive in the market. All this emphasizes the importance of selecting the genotypes with an appropriate photoperiodical reaction.

In 2009, the trials started with mutual intercropping of annual legumes for forage production. Cowpea, adzuki, mung bean, and black gram, with poor standing ability, were deliberately mixed with soybean that acts as a supporting crop. Preliminary results showed that mixtures with cowpea may produce more than 40 t/ha of green manure with a Land Equivalent Ratio (LER) higher than 1, proving its economic reliability.

The first step towards international cooperation in cowpea research involving Serbia is a project with the Prince of Songkla University, aimed at collecting cowpea landraces in Thailand and their complex evaluation in contrasting environments.