Seeds of Matthiola incana contain oil rich (55-65%) in (n-3) linolenic acid. Selected lines were developed and evaluated for their agronomic and chemical parameters. Extracted oil was fed for 6 weeks to rats, which were compared with rats fed a diet containing coconut oil or sunflower oil. Cholesterol levels were significantly lowest in rats fed diets rich in M. incana oil (27% reduction), and triglycerides were significantly lower in rats receiving either M. incana or sunflower oil (36% reduction). The contents of arachidonic acid and other (n-6) fatty acids were significantly the lowest in the liver and plasma of rats that had received M. incana oil. The levels of (n-3) fatty acids were significantly greater in both the liver and plasma of rats fed M. incana oil. The ratio of (n-3)/(n-6) long-chain fatty acids in the plasma was 7 times higher in rats fed with M. incana oil than in those fed with sunflower oil and 6 times higher than in those fed coconut oil. The results demonstrate for the first time a beneficial effect of dietary M. incana oil in reducing cholesterol levels and increasing (n-3) fatty acid levels in the plasma. This new, terrestrial plant source of (n-3) fatty acids could replace marine oils and thereby contribute beneficially to the human diet.

Eruca sativa (rocket) is a native plant of Israel, documented in the old literature. A survey was conducted of the old literature of ancient Israel, including Jewish, Classical and Islamic sources up to the Middle ages. It was found that rocket was used as a garden crop and spice. It was also known as a medicinal plant and was used as an aphrodisiac, for eye infections, and for digestive and kidney problems. It is important to note that special attention was given in the old times to biodiversity within the rocket species. In the light of its high erucic acid content, native accessions were collected and evaluated as a potential future source of industrial oil. Ten accessions of Eruca sativa were cultivated in Bet-Dagan experimental farm during the 1995/96 growing season. Physiological as well as chemical parameters were recorded. Erucic acid (C 22:1) and eicosenoic acid (C 20:1) contents varied from 33 to 45% and from 7.3% to 9.8%, respectively. Special attention was given to the expressed biodiversity among the accessions and its relation to their origins.

Seeds of Sinapis alba L. and Crambe abyssinica L. contain oil, rich in erucic acid (50–60%), which is valuable for industrial purposes. During germination and early growth at 20°C changes in lipid content and fatty acid composition were followed for 15 days. Reduction in the oil content started only 8 days after the onset of germination and was more rapid in C. abyssinica. Oil reduction was accelerated by light and the content reached low levels of 6.7 and 13.7% in seeds of C. abyssinica and S. alba, respectively. No change in dry weight was observed during this period. In cotyledons of S. alba and C. abyssinica respectively, levels of 12 and 25% erucic acid were found after 15 days of development in darkness. Lower levels (4 and 18%) were found in cotyledons developed in the light. No more than 5% erucic acid was detected in the 15-day-old roots of both species. In cotyledons, the decline in erucic acid was accompanied by significant increases in linolenic acid (32% in S. alba and 27% in C. abyssinica) which was also stimulated by light (to 45 and 32%, respectively). No synthesis of linolenic acid was detected in the roots of either species. However, a novel synthesis of saturated palmitic and stearic acids was observed in these species, with a 10-fold increase in their contents. The present results provide an example of the selective utilization of the fatty acids in the reserve oil of seeds during germination and the subsequent growth of seedlings.

Citrulus colocynthis(wild gourd) is a desert plant of the Cucurbitaceae, naturally adapted to arid environments. It was known in biblical times as a source of seed oil and its fruits were used as an efficient laxative. Accessions were collected in Israel and evaluated as a potential oil seed crop adapted to arid zones. It was found that its oil composition is similar to safflower oil, with a total of 80-85% unsaturated fatty acids. A potential yield of oil of 250-400 l ha−1was calculated. The best yield was obtained during the first 4 weeks of the 10-week maturation period. Yield potential should be estimated under desert conditions in order to evaluate the plant's economic future as a crop suitable for an arid environment.

Seeds of Matthiola incana (Brassicaceae) are known to contain oil rich in linolenic acid (C18:3). This oil has a value as a dietary supplement. Commercial lines of Matthiola incana developed for flower production which were kept in our genebank, were tested for their agronomic potential. Five lines were selected for the experiments, all of them excelling in α-linolenic acid content (50–60%). The plants were grown in the experimental stations at Bet Dagan, Jerusalem and Ramat haGolan, representing three different climatic regions. Yield parameters, as well as data regarding oil quality and quantity, were recorded. It was found that under Bet Dagan conditions (Mediterranean climate) a seed yield of 750 kg/ha was obtained. With 20–25% oil in the seed, this yield is equivalent to 150 l/ha. A 50% content of 3-linolenic acid in the oil will yield 75 l of pure linolenic acid.

The oil content, seed yield parameters and fatty acid composition of high- and low-erucic acid Brassica (napus and hirta) seed oils were studied under three different controlled-temperature regimes: low, 12/17 °C; medium, 17/22 °C; and high, 22/27 °C. No fruit set was obtained beyond 27 °C.

Sinapis alba seed accessions (280) were collected from the native flora in Israel, and their oil was analysed for fatty acid composition. The 34 accessions with the highest erucic acid content (above 55%) were grown at the Bet Dagan Experiment Station. Based on their agronomic and chemical performance, 11 lines were selected for a field trial. Following 2 years of cultivation, a significant improvement wasobtained in yield (44%), oil content (15%), erucic acid content (2%) and seed size (17%). Evaluating three selected lines in different geographical locations showed that a cooler climate promotes greater oil content and seed size. However, the best seed yield was obtained in the temperate climate of the Bet Dagan Experiment Station. Line ‘Bet Dagan’ was the best with a yield potential of 665 kg erucic acid per hectare. Based on the results of this work, S. alba can be considered as a potential new oil crop for industrial purposes.

ABSTRACT Seeds of early-, middle- and late-flowering breeding lines of common stock, Matthiola incarta (L.) R. Br. cultivated under field conditions, were evaluated for their fatty acid compositions. Seeds of early-flowering breeding lines accumulated less linolenic acid (C 18:3) and more oleic acid (C 18:1) than those of late-flowering breeding lines harvested at the same time. Yield parameters, such as number of seeds per pod and number of pods per plant were lower in early-flowering breeding lines than in the late-flowering ones. However, under a controlled-temperature regime, the fatty acid compositions of all breeding lines were affected by temperature in the same manner: higher linolenic acid levels and lower oleic acid levels were observed in seeds which developed at lower temperatures (12–17 °C).

Seeds from 15 Cruciferae species, native to Israel, were collected and examined for fatty acids in order to identify species rich in fatty acids with potential for industrial use from the wild gene collection. In species rich in erucic acid (22:1), such as Crambe and Sinapis a low content of polyunsaturated linolenic acid (18:3) was found; the same negative correlation was observed in species low in erucic acid (Matthiola, Lepidium), in which 64 and 42% linolenic acid, respectively was found. No correlation was detected between the content of erucic and oleic acids, as opposed to the situation in cultivated rape seeds. Plants with different oil compositions were found in the same natural habitat. Fatty acid profiles could not be related to ecological conditions.