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• Comparative study of some nutritionally important components on different cabbage (Brassica oleracea L.) genotypes

  81-84.

  É. Sárdi

  E. Tordai

  E. Németh

  É. Stefanovits-Bányai

  Views:

  151

  Vegetables of Brassicaceae are especially important because of their inner values, which play a provably positive role in curing and preventing diseases. Cabbage (Brassica oleracea L. convar. capitata provar. capitata) is still today one of the most frequently consumed green vegetables, which is known to brake the absorption of carcinogenous substances and to obstruct cell mutation. Different cabbage cultivars were compared growing under the same circumstance. The level of different carbohydrate fractions and some biologically active quaternary ammonium compounds were determined. In all cases we analyzed the antioxidant capacity of samples characterizing the free radical scavenging capacity.

  Clearly detectable significant differences were found between the varieties tested, which appeared suitable for selecting the most precious varieties for human nutrition.

• Evaluation of biological control option for Bagrada bug (Bagrada hilaris (Burmeister)) in Kenya

  43-47.

  N. Otieno

  M. Saidi

  A. Opiyo

  M. Kasina

  M. Guantai

  Views:

  86

  Brassica production is important for economic development of Kenya. Bagrada bug, a significant pest of brassicas, affects their yields and quality, currently posing a threat to both local and commercial vegetable production in Kenya. Biological control of bagrada bug using natural enemies is a cheaper and environmentally friendly method. The study aimed to identify native egg parasitoid species in Kenya. A field prospection survey of the bagrada bug egg parasitoid was done by a series of bagrada bug egg exposure in different parts of the country. Freshly laid bagrada bug eggs in cards were exposed for possible parasitism in the field for three days. The eggs were later carried to the laboratory at NSRC to await hatching. Two egg parasitoid species Trissolcus basalis (Hymenoptera, Scelionidae) and Gryon sp. were identified during the study after a period of bagrada bug egg exposure in Machakos and Kisumu. Two cards with parasitized bagrada bug eggs were recovered from Machakos from which one card yielded four parasitoids of one species Trissolcus basalis and the other yielded two parasitoids Trissolcus basalis and Gryon sp. One card with two parasitized eggs by Trissolcus basalis was recovered from Kisumu, however, there were no parasitoids identified in Nanyuki, Naivasha and Kitengela where bagrada bug is also prevalent. Results showed parasitoid presence in fields with high bug populations compared to areas with few or no Bagrada bug infestations. Conducting trials in both laboratory and field settings is recommended to obtain clear data on the effectiveness of the identified egg parasitoid in managing the bagrada bug population.

• Effects of nitrogen fertilizer application rate and time to first harvest on leaf area index; leaf nitrate content and yield of irrigated leaf rape (Brassica napus L. var. Giant)

  64-75.

  J. Masaka

  M. Chandiposha

  B. T. Makaure

  B. Mazina

  Views:

  271

  In Zimbabwe, smallholder cultivation of leaf rape is of considerable importance due to the increasing demand for the leaf vegetable from the rapidly increasing urban populations.  A two-season field trial was conducted in the Agricultural Practice Experimental Plots of the Midlands State University in central Zimbabwe. The objective of the study was to establish selected biometric responses of leaf rape to N fertilizer rates and time to first harvesting. Increasing the rate of N fertilizer application considerably improves the yield of fresh rape leaf; LAI and concentration of leaf nitrate. Delaying rape leaf harvest after N fertilizer side dressing can be used as a strategy to boost rape leaf yield for vegetable markets with high single delivery demand. When harvesting is deliberately delayed after N fertilizer application rape LAI are significantly increased. Delaying the first leaf harvests by 7; 14 and 21 days after N fertilizer side dressing amendments increases the content of nitrate in fresh rape leaves. Fresh rape yield can be more accurately predicted by values of rape LAI. Nitrate concentrations in fresh rape leaf is a poor predictor of rape yield under field conditions.