AJOL: African Crop Science Journal: Volume 8, No 2, June 2000 Abstracts

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Volume 8, No 2, June 2000
Twenty Seventh Issue

African Crop Science Journal, Vol. 8. No. 2, pp. 109-116, 2000
ISSN 1021-9730/2000

NUCELLAR EMBRYO CULTURE OF CITRUS SINENSIS L. AND CITRUS LIMON L.

S. D. OBUKOSIA and KIMANI WAITHAKA
Department of Crop Science, University of Nairobi, P.O. Box 29053, Nairobi, Kenya

(Received 5 September, 1997; accepted 10 May, 2000)

ABSTRACT

Nucellar tissue cultures of polyembryonic Citrus sinensis cultivar Valencia Late and Citrus limon cultivar Rough Lemon produced somatic embryos within 60 days of culture on Murashige and Skoog (MS) basal medium supplemented with 0.4 g l-1 of filter-sterilised casein hydrolysate or 10% coconut water. Embryos that were separated and subcultured in MS media containing casein hydrolysate or coconut water but without hormones, first developed roots within 4 to 8 months and then shoots within 6 to 9 months of in vitro culture. Plantlets were transplanted to soil from 7 to 9 months after initiation. Callus-like tissue consisting of pseudobulbils was observed after 4 to 5 months from the time of initiation. Pseudobulbils developed into visible embryos with multiple cotyledons when subcultured into MS media containing casein hydrolysate or 10% coconut water after 19 to 27 days of in vitro culture. These embryos produced plantlets in which roots developed after 6 to 10 months and shoots formed after 8 to 11 months from the time of initiation.

Key Words: Citrus, nucellar embryo culture, somatic embryogenesis

African Crop Science Journal, Vol. 8. No. 2, pp. 117-127, 2000
ISSN 1021-9730/2000

Comparison between Embryoid and Shoot Primordia Methods of Plantlet Production for'`Asiatic Hybrid Lily' and '`Oriental Hybrid Lily'

H. Sugiura, S.G. Agong , A. Enami¹, H. Kaneko and T. Honma²
Department of Horticulture, Faculty of Agriculture, Jomo Kenyatta University of Agriculture and Technology, P. O. Box 62000, Nairobi, Kenya
1Niigata Agricultural Extension Centre, 18-1 Kawagishi-chyo-3 Chome Niigata, 950-8133, Japan
2Niigata Horticultural Experiment Station, 177 Mano Seiro Niigata, 957-0111, Japan

(Received 19 October, 1999; accepted 14 June, 2000)

ABSTRACT

Growth and development from shoot primordia and embryoids obtained from the Asiatic Hybrid Lily and the Oriental Hybrid Lily were studied. Shoot primordium and embryoid formation of the Asiatic Hybrid Lily was more successful than the Oriental Hybrid Lily. The highest shoot primordium formation medium of the Asiatic Hybrid Lily from apical meristem was achieved at 0.5 BA (6-benzylaminopurin) without NAA (nafthalen acetic acid), and that of the Oriental Hybrid Lily required 0.01 mg/l NAA and 0.5 mg/l BA. Embryogenic calli from the shoot apex for embryoid germination gave rise to numerous embryoids, which regenerated rapidly in the medium with the same concentrations of NAA and BA in the medium for shoot primordium formation. Concentrations of NAA and BA in the medium for regeneration from shoot primordium and embrioids were similar to treatment for shoot primordium and embryoids formation but differed between the Asiatic Hybrid Lily and the Oriental Hybrid Lily. Young plants regenerated in vitro from shoot primordium and embryoids acclimatised with the maintenance of humidity. Only a few cases of somaclonal mutation were noted in the regenerated plants from shoot primordium and embryoids. Thus, our results suggest that plantlets produced by these methods are stable and commercial production via this protocol is feasible for lily propagation.

Key Words: Asiatic Lily, mutation, propagation, shoot primordial

African Crop Science Journal, Vol. 8. No. 2, pp. 129-136, 2000
ISSN 1021-9730/2000

INTERSPECIFIC HYBRIDISATION OF LATHYRUS SATIVUS (GUAYA) WITH WILD LATHYRUS SPECIES AND EMBRYO RESCUE

G. ADDIS and R.K.J. NARAYAN1
Ethiopian Health and Nutrition Research Institute, P. O. Box 1242, Addis Ababa, Ethiopia
1Institute of Biological Sciences, University of Wales, Aberystwyth

(Received 27 October, 1998; accepted 2 February, 2000)

ABSTRACT

Lathyrus sativus is an economically important legume crop cultivated for food and forage in Asia and Africa. The use of this hardy drought tolerant and high yielding crop, however, has been limited because of a neurotoxin, _-N-oxalyl-L-_,_-diaminopropionic acid (ODAP) in the seeds. The objective of this study was to increase the genetic diversity of L. sativus by interspecific hybridisation with wild Lathyrus species devoid or with very low ODAP content. This would in turn assist to study the biochemical and genetic mechanisms which control the biosynthesis of ODAP. L. sativus was crossed with 12 wild Lathyrus species. Except for the reciprocal crosses of L. sativus and L. pseudo-cicera, others failed to develop viable seeds. In several of the interspecific hybrids, pod development was observed but embryos aborted during early stages of development. Embryo culture was attempted to rescue these immature embryos. The response of the interspecific hybrid embryos to in vitro culture varied. Cell proliferation and callus induction were observed in most of the combinations, and mature plants were regenerated from immature embryos of a cross between L. sativus (male parent) and L. cicera (female parent) both of which contain ODAP. However, it is expected that, with few modifications, this method will be useful in other interspecific hybrid combinations of Lathyrus.

Key Words: Hybridisation, Lathyrus, lathyrine, Neurotoxin, ODAP

African Crop Science Journal, Vol. 8. No. 2, pp. 137-143, 2000
ISSN 1021-9730/2000

PHENOTYPIC DIVERSITY IN THE ETHIOPIAN NOUG GERMPLASM

Tsige Genet and Ketema Belete¹
Adet Research Centre, P.O. Box 8, Dahir Dar, Ethiopia
1Alemaya University of Agriculture, P.O. Box, 138, Dire Dawa, Ethiopia

(Received 31 March, 1999; accepted 27 February, 2000)

ABSTRACT

Noug (Guizotia abyssinica (L.f.) Cass.: 2n = 30), a member of the Compositae family, is grown as an oilseed crop in Ethiopia. The crop grows best on poorly drained heavy clay soils. In this experiment, 157 noug accessions randomly sampled from different parts of the country were evaluated in a field test at Adet, Ethiopia in 1993, to estimate the phenotypic diversity index (H') for phenological (days to flowering, days to maturity) and morphological (leaf colour, leaf margin, stem hairiness, stem colour, angle of branching, plant height) characters. The phenotypic diversity was calculated using Shannon-Weaver diversity index (H') for the regions, provinces, characters, after pooling together all characters. The results of this study indicated that the phenotypic diversity index (H') of noug accessions was 0.61 for Western, 0.56 for Northern, 0.54 for Southern and 0.51 for Central and Eastern Ethiopia Province, while the highest diversity index was from Gojjam H' = 0.60, Welega H' = 0.57, and Shewa H' = 0.53. The phenotypic diversity index for the Nation was H' = 0.40. Most of the variations were due to differences among provinces for different characters than among regions. Based on the characters studied and small collections evaluated, the centres of diversity for noug appears to be in Gojjam, Welega and Shewa, and further exploration efforts should be undertaken in these regions.

Key Words: Diversity index, genetic diversity, germplasm, Guizotia abyssinica Cass., oilseed

African Crop Science Journal, Vol. 8. No. 2, pp. 145-152, 2000
ISSN 1021-9730/2000

VARIABILITY BETWEEN LOCAL AND EXOTIC BAMBARA GROUNDNUT LANDRACES IN BOTSWANA

S. K. KARIKARI
Department of Crop Science and Production, Botswana College of Agriculture,
Private Bag 0027, Gaborone, Botswana

(Received 3 March, 1999; accepted January, 2000)

ABSTRACT

Nine landraces of Bambara groundnut (Vigna subterranea (L) Verdc.), seven from the Botswana collection and one each from Zimbabwe and Tanzania, were evaluated to exploit the variability between them. The results indicate that four landraces namely GABC, TSHC, BOTR and DIPC were early, maturing within 120 days. Other medium duration landraces , 120 - 128 days were OM1, OM2 and NTSR. Two other landraces, OM6 and DOR were late season maturing in 133 and 165 days, respectively. The early maturing landraces (except BOTR) were high yielding because they emerged rapidly, flowered within 40 days, and had enough time to mature their pods before the advent of unfavourable weather due to less moisture and decreased temperature. Of the desirable agronomic parameters correlated with grain yield, 100 seed weight, shelling percentage and total dry matter had high heritability and could therefore be used in Bambara groundnut improvement programmes in Botswana and areas with similar climate.

Key Words: Heritability, variance component, 100 seed weight, Bambara groundnut, Botswana collection

African Crop Science Journal, Vol. 8. No. 2, pp. 153-157, 2000
ISSN 1021-9730/2000

ADAPTATION OF COTTON CULTIVARS

ABDISHEKUR WONDIMU
Ethiopian Agricultural Research Organisation (EARO), Awassa Research Centre,
P. O. Box 6 Awassa, Ethiopia

(Received 6 October, 1997; accepted 14 June, 2000)

ABSTRACT

A set of 12 cotton genotypes were evaluated during the main growing seasons, from 1985 to 1990 at Abobo , which is characterised by low elevation (530 meters above sea level) and a sub-humid climate. The same genotypes were tested in all years. Combined analysis of yield data indicated significant differences among genotypes and environments. Genotype-environment interaction was highly significant, indicating differential performance of the cultivars in an array of environments. For each cultivar a linear regression of yield on the mean yield of all cultivars for each year was computed to measure cultivar adaptation. The cultivars with the highest mean yield exhibited a similar degree of adaptation to different environments with regression coefficient close to 1.0. For example, the breeding lines, Acala 1517Br x AMS1 (74)#11, A-333-57, showed average stability with regression coefficient (b) approximating 1.0, and all produced above average yield in all years indicating general adaptability. On the other hand, Albar 637 and Reba B-50 also had regression coefficient (b) approximating 1.0, but they consistently produced below average yields in different environments which indicated that they were poorly adapted to different environments. The check cultivar ( L-299-10), typical of cultivars specifically adapted to high yielding environments, was characterised by the highest regression coefficient (b=1.2), while Lafrego bract 2, with regression coefficient (b=0.85), typified cultivars specifically adapted to low yield.

African Crop Science Journal, Vol. 8. No. 2, pp. 179-186, 2000
ISSN 1021-9730/2000

FIELD REACTION OF CASSAVA GENOTYPES TO ANTHRACNOSE, BACTERIAL BLIGHT, CASSAVA MOSAIC DISEASE AND THEIR EFFECTS ON YIELD

C.N. Fokunang, T. Ikotun, A.G.O. Dixon¹ and C.N. Akem¹
Department of Crop Protection and Environmental Biology, University of Ibadan, Oyo State, Nigeria ¹International Institute of Tropical Agriculture, PMB 5320, Oyo Road, Ibadan, Nigeria

(Received 9 October, 1998; accepted 20 January, 2000)

Abstract

Thirteen cassava genotypes were evaluated at the International Institute of Tropical Agriculture, Ibadan, Nigeria for anthracnose (CAD), bacterial blight (CBB) and cassava mosaic disease (CMD) incidence and severity, and their effects on yield, for three consecutive planting seasons. There were significant differences (P<0.05) in CAD, CBB and CMD incidence and severity amongst the cassava genotypes across the planting seasons. Yield assessment showed significant differences (P<0.05) in storage root number, plant stand, root fresh weight and dry matter content among the cassava genotypes. There was no significant variation in tuber rot among the genotypes, and 80% of the genotypes did not show any tuber root rot when harvested 12 months after planting. CBB and CAD incidences were significantly and positively correlated (r=0.43), whereas CBB and CMD incidences were not significantly correlated (r=0.03). CAD and CMD incidence and severity were highly correlated (r=0.82 and r=0.76, respectively). CBB incidence was negatively correlated with storage root weight and fresh root tuber number (r=-0.45 and r=-0.48, respectively). CMD severity showed a significant negative correlation with storage root weight (r=0.44). Cassava genotypes TMS 30001, 30211 and 88/01087 showed a stable resistance over 3 planting seasons to CAD, CBB and CMD.

Key Words: Colletotrichum gloeosporioides f.sp. manihotis, disease interactions, host resistance, Manihot esculenta, Xanthomonas campestris pv. manihotis

African Crop Science Journal, Vol. 8. No. 2, pp. 187-193, 2000
ISSN 1021-9730/2000

TWO BARLEY YELLOW DWARF LUTEOVIRUS SEROTYPES ASSOCIATED WITH STUNTING OF IRRIGATED WHEAT IN ZAMBIA

J. NDUNGURU* and R. G. KAPOORIA¹
Maruku Agricultural Research Institute, P. O. Box 127, Bukoba, Tanzania ¹Department of Biological Sciences, University of Zambia, P. O. Box 32379, Lusaka, Zambia
(* Present address: Plant Protection Division, P. O. Box 1484, Mwanza, Tanzania)

(Received 1 March, 1999; accepted 3 March, 2000)

ABSTRACT

Barley yellow dwarf luteovirus (BYDV) serotypes PAV and RPV were identified from irrigated wheat (Triticum aestivum L.) samples from three provinces of Zambia by double antibody sandwich enzyme-linked immunosorbent assay using polyclonal and monoclonal antisera. Nine wheat cultivars were surveyed in 11 wheat fields. The virus caused stunting of the infected plants and leaf yellowing. The BYDV-PAV and BYDV-RPV serotypes were identified from 9 and 10 of the 11 surveyed fields, respectively, with the two serotypes co-infecting some plants. Of the nine wheat cultivars surveyed, four were infected with PAV, one with RPV and four with both serotypes. Disease incidence caused by BYDV in the surveyed fields ranged from 5 to 25%. This is the first report on the occurrence of BYDV in wheat in Zambia.

Key Words: Barley yellow dwarf Luteovirus, detection, serology, serotypes, symptoms

African Crop Science Journal, Vol. 8. No. 2, pp. 195-201, 2000
ISSN 1021-9730/2000

SHORT COMMUNICATION
Chemical composition of Ricinodendron heudelotii: an indigenous fruit tree in southern Cameroon

T. Tiki Manga, J. M. Fondoun, J. Kengue and C. Thiengang¹
IRAD/CRRAN, P. O. Box 2067, Nkolbisson, Yaoundé, Cameroon ¹Université de Ngaoundéré, P. O. Box, 455 Ngaoundéré, Cameroon

(Received 25 May, 1998; accepted 4 February, 1999)

ABSTRACT

An ethnobotanical survey and germplasm collection of Ricinodendron heudelotii (Bail.) (an indigenous fruit tree) were carried out in six provinces of the humid rainforest zone in southern Cameroon. Fruit samples were collected at 40-50 km intervals along the main road network of the zone, from homegardens, food crop as well as cash crop fields, bush fallow and primary forest land uses. At each point, 100 fruits were randomly collected under a tree chosen by farmers. A total of 47 accessions or tree provenances were sampled in 47 different villages. Kernels (cotyledons) or the edible parts of these fruits were analysed for fat, crude protein, ash and crude fibre. Total carbohydrates and energy values were also determined. The edible parts of Ricinodendron heudelotii were found to have a very high fat content (49.2 to 63.5 %) and crude protein (49.9 to 65.2%), and low total carbohydrates (4.9 to 6.4 %). The highest values for crude fibre and total ash were 9.37 and 17.76%, respectively. The species also gave higher energy values (2,748 to 3,558 KJ 100g-1 DM) as compared to food crops (84-2500 KJ 100 -1 DM). Two provenances, FTKC 27 and FTKC 32, were classified as high and low energy “ideotypes”.

Key Words: Ricinodendron, nutrition, quality

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African Journals Online African Crop Science Journal

Volume 8, No 2, June 2000 Twenty Seventh Issue

African Journals Online
African Crop Science Journal

Volume 8, No 2, June 2000
Twenty Seventh Issue