Establishment and yield ofminisetts of yam (Dioscorea rotundata Poir) as influenced by size and position of minisett on mother tuber and by staking in the field

Two experiments were conducted in 1985 and 1986. Yam vines emerged earlier from the head and tail minisetts than the middle minisetts. Higher percent plant establishment recorded in bigger minisetts occurred only in those setls that originated from the head and tail positions of the mother tuber (head, middle and tail). However, there was no difference between treatments in the final percent plant establishment at 12 weeks after transplanting (WA TP), In the 1985 experiment, effect of staking on yield of yam plants derived from minisetts was significant. Yields of seed yam were, however, higher from plants derived from bigger (25-35 g) than smaller (10-20 g) setts, In 1986, this pattern was maintained. Seed yams produeed by head minisetts weighed significantly more (314.7 g/plant) than those produeed by the middle minisetts (265.8 g/plant), Tuber yield per hectare followed the same pattern. The percent yield of marketable tubers (200 g or more per tuber) from the. head minisetts (68.8 %) was similar to that from the tail (61.7 %) but differed significantly (P 0.01) from that of the middle minisetts (49.3 %), Higher percentage of marketable tubers was obtained with increase in minisett size

Pre-tillage control of spear grass (Imperata cylindrzca [L.] Raeuschel) with Glypnosate for soya bean (Glycine max [L.] Merr.) production in Nigeria

No Abstract Available E. Afr. Agric. For. J Vol.68(3) 2003: 155-15

FUZZY MODELING BY SUCCESSIVE ESTIMATION OF RULES

This paper presents an algorithm for automatically deriving fuzzy rules directly from a set of input-output data of a process for the purpose of modeling. The rules are extracted by a method termed successive estimation. This method is used to generate a model without truncating the number of fired rules, to within user specified accuracy and without requiring an in-depth understanding of the underlying process. Results obtained by the algorithm are in good agreement with the available data on the speed-current characteristics of a dc series motor. JMDMES Vol.2(1) 2003: 71-8

Modulating Effect of Black Plastic Mulch on the Environment, Growth and Yield of Cassava in a Derived Savanna Belt of Nigeria

The modulating effect of black plastic mulch on the crop growing environment, crop growth and yield of two improved cassava (Manihot esculenta Crantz) varieties (TMS 30572 and TMS 4(2) 1425) bred by International Institute of Tropical Agriculture (IITA) was studied in a soil described as Typic Paleustult at the Faculty farm of University of Nigeria, Nsukka, a derived savanna belt of Nigeria. The experimental design was a 2 x 2 factorial arranged in a randomized complete block design (RCBD) with four replications. Results show that black plastic mulch influenced a 100% weed control in the plots mulched and raised the morning (09.00 GMT) soil temperature to 46%. Moisture evaporation was effectively controlled as water vapour condensed beneath the plastic mulch and fell back as droplets into the soil. The fresh root tuber yield of the cassava varieties was increased to 40.7% (TMS 30572) and 48% (TMS 4(2) 1425) while the leaf area increased from 292.5 cm2 to 572.8 cm2 in TMS 30572 and from 266.9 cm2 to 428.5 cm2 in TMS 4(2) 1425 by the plastic mulch. Generally, all growth and yield parameters measured were significantly (P> 0.05) improved by the application of black plastic mulch