Pulse domestication: Fact and fiction

Abstract

In his paper "Pulse domestication and cereal domestication: how different are they?" (this issue), Zohary takes issue with a report (Ladizinsky 1987) that offers a new insight into the problem of pulse domestication in light of recent evidence that may be summarized as follows: (1) Wild progenitors of pulses in the Middle East are ecologically restricted, grow in small populations and produce a small number of seeds per plant. As an example, about 10,000 plants of wild lentil have to be collected in order to provide 1 kg of clean seeds. Wild cereals, on the other hand, usually grow in massive stands, so that one can collect enough seeds during the spring to support oneself throughout the year (Harlan 1967; Ladizinsky 1975). (2) Strong seed dormancy is typical of wild pulses. For example, about 10% of wild lentil seeds are capable of germinating in the following season. Obviously then, little or no gain of seeds can be obtained by planting wild lentil for food. In contrast, 50% of the seeds of wild wheat normally germinate in the following season, and because of their enormous tillering ability they may produce a normal yield. Nevertheless, Zohary continues to propound his notion that cereals and pulses in the Middle East underwent the same pattern of domestication. It is worth analyzing Zohary's arguments point by point, in the light of the above evidence. Point no. 1 in his paper is merely a repetition of his previous assertion that the patterns of cereal and pulse domestication are parallel, without any new evidence to support it. In point no. 2, Zohary suggests that grazing is a major factor in the reduction of the yield of wild lentil seeds and that yearly fluctuations are also directly affected by climatic conditions. If this argument is intended to imply that the values presented by Ladizinsky (1987) are underestimates of the yield potential of wild lentils in their natural habitat, it is pertinent to note that two of the three populations tested were entirely free of grazing yet they yielded practically the same amount of seeds as the third population where grazing was common. Futhermore, in the year in which these populations were tested the rainfall was above average. These three populations of wild lentil, as well as others, were revisited during the last 2 yr for further evaluation of their yield potential. In both years all of these populations were extremely poor, consisting of small numbers of plants which bore one to three pods per plant. It therefore seems that the data presented by Ladizinsky (1987) were if anything an overestimate of the average yield of wild lentils. If, on the other hand, Zohary means that grazing was a limiting factor for seed collection in preagricultural times, it would be instructive if he could indicate which animals were involved and what evidence there is to support this notion. In point no. 3 and later in the paper, Zohary attempts to convince the reader that, in tilled plots and with supplementary irrigation, wild lentil can produce 4070 seeds per plant. There is nothing new in this to anyone who has grown wild plants under favorable conditions. The real question, however, is whether the