A review on evaluation and agronomy of promising lupine varieties in Kenya

F.N. Muyekho

Forage Agronomist
National Agricultural Research Station
P.O. Box 450, Kitale, Kenya

Introduction
Results
Discussion
Conclusion
Acknowledgements
References

Abstract

This review deals with a series of agronomic and evaluation work on promising lupine varieties in major agroecological zones of Kenya. The trials examined regional performance of different varieties of lupine and the effects of inoculation and phosphatic fertilization. Results from early observation trials indicated that lupines performed better in the medium and high altitude, high potential areas. Other areas appeared unsuitable for this crop partly due to inadequate moisture levels.

Reported observations showed that cultivars Unicrop and Ultra were early maturing and were relatively shorter in height compared to Uniwhite and Uniharvest both of which were taller and later maturing. Moreover, further work revealed that cultivars Uniharvest, Ultra and Uniwhite had higher grain yield and higher protein (42.8%, 40.7% and 35.8% respectively) compared to Unicrop (31.0%). Cultivar Ultra was the highest seed yielder. Only small increases in seed yield and quality were reported when inoculants and phosphatic fertilizers were used suggesting that these treatments may not be beneficial under certain conditions.

Introduction

Lupines are annual or perennial legumes belonging to the genus Lupinus which contains 250 species (Highes et al., 1952). Most of these are native to America. The large-seeded species of commercial importance, however, are all native to the Mediterranean basin in Europe. These include blue lupine (L. angustifolius and L. hirsutus), white lupine (L. albus) and the yellow lupine (L. luteus). Others are the Spanish lupine (L. hispanicus) and Texas lupine (L. mutabilis) which have been used for more than 3000 years as a subsistence crop in the Andean Highlands (Lees, 1979). Some of the cultivated lupines are bitter and unpalatable but excellent producers of nitrogen.

In Kenya, there are two species of sweet lupines whose agronomy and nutritive evaluation has received considerable attention. These are the blue lupine cultivars Uniwhite, Uniharvest and Unicrop and the white lupines represented by the cultivar Ultra (Wanjala, 1979). All of them are annual in nature. These varieties with high foliage, grain yields and high crude protein content were shown to take 4-7 months to mature depending on variety (Gladstones, 1970; Wanjala, 1979). The main objective of conducted work on lupine in Kenya was to establish a cheap source of protein as a concentrate for livestock supplementation. Trials undertaken at the National Agricultural Research Station, Kitale, included testing the adaptability of lupine varieties in different agroecological zones (Bauer and Oketch, 1976), the observation of physiological characters of lupine varieties grown under uniform conditions (Kusewa et al., 1977), the comparison of herbage dry-matter yield (Kusewa et al., 1980, 1981) and the investigation on the effect of phosphatic fertilizers and inoculation on seed production of the lupine variety Ultra (Kusewa et al., 1980, 1981).

Results

Lupine Regional Adaptability

Based on rainfall and altitude Bauer and Oketch (1976) have reported on the adaptability of lupines in nine sites in Kenya (Table 1). The lupines were planted at a recommended spacing of 50 x 30 cm, Bauer and Oketch (1975) in unreplicated plots.

Table 1. Performance of lupine varieties in different agroecological zones of Kenya.

	Altitude (m)	Rainfall² (mm)	Height (cm)	Variety	Seed yield t/ha	Remarks
Molo	2740	1015-1270	110	Ultra	-	Slow to swell
Eldoret	2130	1015-1270	119	Ultra	1.8	Lodging
Nyandarua1	2331	760-1015	100	Ultra	-
Kitale	1980	1015-1270	60-140	Ultra	1.7
				Uniharvest	2.2
				Uniwhite	1.8	Lodged
				Unicrop	1.2	Shortest
Kakamega	1580	1780-2030	87	Ultra	1.4	Seed shattering
Embu	1460	760-1015	79	Ultra	0.81
Katumani1	1680	510-760	41	Ultra	-	All poor and diseased
				Uniwhite	-
				Uniharvest
				Unicrop
Kiboko1	1000	300-650	39	Ultra, Unicrop	-	Pods were weak
Mtwapa1	12	1015-1270	25	Ultra, Unicrop
				Uniwhite, Uniharvest		Poor and diseased

Source: Bauer and Oketch (1976).
¹ Seed yield not available.
² Source of mean annual rainfall: National Atlas of Kenya, third edition, 1970.

Medium and high altitude, high potential regions such as Kitale, Molo, Eldoret, Kakamega and Embu proved to be the most promising sites for growing sweet lupines. Hot and dry areas such as Katumani and Kiboko as well as the hot and wet areas such as Mtwapa (Mombasa) proved unsuitable. There are indications that for better yields, lupines need 5 months free of serious moisture stress and mean monthly maximum temperatures ranging from 15 to 25°C (Wanjala, 1979). These conditions are typical of the areas where lupines produced favourable results.

Physiological Development of Lupine Varieties

Physiological development of four lupine varieties grown under uniform conditions was observed at Kitale (Kusewa et al., 1977). The four lupine varieties Uniwhite, Unicrop, Ultra and Uniharvest were inoculated with group "G" inoculant before planting. Single superphosphate fertilizer at the rate of 40 kg/ha P₂O₅ was applied at planting. A spacing of 50 x 30 cm was used with two seeds per hill at planting.

It was shown (Table 2) that Unicrop and Ultra were early maturing and were short and medium in height, respectively. On the contrary, Uniwhite and Uniharvest were tall and late maturing. Uniwhite was more susceptible to lodging than any of the other varieties studied. Field observations also indicated that Unicrop was the most susceptible to powdery mildew. Considering seed weight, Ultra had a higher weight per 100 seeds than all the other varieties. It also had more pods/plant than the others.

Table 2. Physiological development of lupine varieties.

Observation	Variety
	Uniwhite	Unicrop	Uniharvest	Unicrop
Days to germinate	5	5	5	5
Days to 80% flowering	125	49	91	49
Lodging (%)	30	0	10	15
Days to maturity	202	120	202	150
Shattering of seed (%)	30	5	5	5
Plant height (cm)	140	60	115	110
Pods per plant	28	19	27	45
100 seed weight (g)	17.3	19.3	17.5	43.5

Source: Kusewa et al. (1977).

Productivity and Evaluation of Lupine Varieties

Kusewa et al. (1980, 1981) conducted a trial at Kitale to determine herbage dry matter, seed production and nutritive value of four' lupine varieties; Unicrop, Uniwhite, Uniharvest and Ultra. They were planted under recommended establishment practices similar to those of the physiological development study. The lupines were harvested at three stages of growth i.e. 2, 3 and 4 months after establishment. A single plot was included per variety for the determination of seed at physiological maturity.

Significant differences (P<0.01) were observed in both herbage dry-matter and seed yield among varieties and harvesting stages (Table 3). Variety Ultra was outstanding in both herbage and seed yield. During 1980, maximum herbage yield for Ultra, Uniharvest and Uniwhite were obtained when they were cut at four months but highest yield for Unicrop was attained at three months. In 1981, however, all the varieties had the highest herbage yield when harvested at four months. Crude protein (CP) values and in vitro digestibility values (Table 4 and 5) were higher in the grains than in the herbage in all the four lupine varieties investigated.

Table 3. Performance of lupine varieties harvested at different stages.

	Herbage DM production kg/ha
	2 months		3 months		4 months		Seed yield (kg/ha)
Harvesting stage	1980	1981	1980	1981	1980	1981	1980	1981
Unicrop	760	140	1612	610	1260	990	350	260
Uniwhite	510	120	2764	410	3074	1620	947	890
Uniharvest	616	180	2227	820	4426	2590	750	1190
Ultra	692	166	3400	2180	4300	6180	3344	4000

Source: Kusewa et al. (1980, 1981).

Table 4. Effect of stage harvesting on the crude protein content of lupine varieties.

	Harvesting stages (CP %)						Seed at physiological maturity
	2 months		3 months		4 months		(CP %)
Variety	1980	1981	1980	1981	1980	1981	1981
Unicrop	21.9	25.4	16.4	26.8	14.3	23.9	31.0
Uniwhite	19.0	25.0	17.8	28.6	14.3	8.2	35.8
Uniharvest	21.0	20.4	18.9	10.7	17.3	19.6	42.8
Ultra	20.2	16.6	15.9	23.5	14.3	13.6	40.7

Source: Kusewa et al. (1980, 1981).

Table 5. Effect of stage of harvesting on the digestibility values of lupine varieties.

Variety	D-value	D-value	D-value	D-value
Unicrop	62.2	65.2	57.6	85.5
Uniwhite	64.3	65.0	56.0	88.8
Uniharvest	62.7	64.1	54.7	88.7
Ultra	66.2	67.5	74.2	84.0

Source: Kusewa et al. (1980).

Phosphate fertilizer and inoculation requirements of lupines

A trial conducted by Kusewa et al. (1980, 1981) examined the seed production of lupine cv Ultra when inoculated and fertilized with phosphates at the rates of, 100, 200, 300 kg/ha P₂O₅. Inoculation resulted in more nodule formation per plant whereas phosphate fertilizer application did not have any effect on nodulation between the inoculated and non-inoculated lupine plants (Table 6). Differences in seed yield and percent protein content were not significant suggesting that inoculation and phosphatic fertilization were not beneficial under Kitale conditions.

Discussion

The four sweet lupine varieties tested were shown to do well in medium and high altitude, high potential areas of Kenya. The lupines did not do well in hot and dry areas because of the moisture stress. These results are in agreement with those of Heath et al. (1975) who had reported that lupines required cool weather for best development. Savile and Wright (1958) reported that sweet lupines grow at altitudes between 2225 and 2743 m and bitter lupines from 1981 to 2743m. It would, however, appear that sweet lupines can still do well at lower altitudes than those recommended by Savile and Wright as evidenced by studies conducted by Heilbutch (1952); Poultney (1963); Bauer and Oketch (1976) and Wanjala (1979). They reported promising results in Kitale at a lower altitude of 1980 m.

The cultivar Ultra outyielded other varieties (Table 3) due to development of numerous pods and heavier seeds. This result would appear to contradict earlier observation (Table 1) where Ultra was outyielded by Uniharvest and Uniwhite. However, experiments conducted by Bauer and Oketch (1975, 1976); Kusewa et al. (1977) and Wanjala (1979) confirm that Ultra is superior to the others in seed yield. Two farmers in Kitale reported a seed yield of 780-1100 kg/ha in 1951 and 780-1900 kg/ha in 1952 for sweet blue lupines (Heilbutch, 1952). This is within the range reported in Table 1.

Table 6. The effects of inoculation and phosphate fertilization of lupi cv Ultra.

Lack of response of sweet lupine varieties to inoculation and phosphate fertilization indicates that lupines can still be grown in Kitale without such treatments. The lack of response could be attributed to the fact that soils in Kitale have levels of phosphate adequate to support lupine growth. The results agree with those of Henderson and Preston (1959) who recommended that application of phosphate should only be done on soils of very low fertility. Work by Bauer (1976) on lupine cv Ultra gave similar results.

Inoculation should have resulted in greater nodulation hence higher seed yields. However, this was not so and could be attributed to ineffective nodulation. This argument is in line with that of Henderson and Preston (1959) who reported good nodulation of uninoculated crops in most areas of Kenya, although they noted that most of the nodules were ineffective. Work carried out by Wanjala et al. (1983) in one farmer's field showed a significant seed-yield response of sweet lupine cv Ultra to inoculation but not to phosphate fertilizer. A more comprehensive study by de Souza (1969) when working on blue lupines found effective natural nodules at twelve sites and no natural nodulation at nine sites.

Experiences gained from this study show that there is need for lupine variety testing trials to be conducted in different ecological zones for herbage and seed yield. There is also need for phosphate and inoculation studies to be conducted in a wide range of sites. Future agronomic interventions of lupine studies should involve a study on the relationship of critical elements like sulphur and molybdenum with seed production and investigations on the effect of planting dates on seed yield for both early and late maturing varieties to avoid seed losses during wet weather. Other aspects to be considered should be intercropping lupine with food crop or other forages with the aim of maximising the utilisation of the ever-diminishing land holdings in the high potential areas.

Conclusion

The high dry-matter yield, percent crude protein and high D-values especially in seed for the various lupine cultivars indicate that there is great potential for the utilisation of lupines as a livestock feed supplement. Further studies aimed at the utilisation of sweet lupines as a feeding material will elucidate the importance of these lupines in the livestock industry.

Acknowledgements

The author wishes to thank Mr. C.W. Mwendia for his technical advice in the writing up of this paper and Mr. R.E. Kamudi for the statistical analyses. Appreciation is extended to Mr. P.K. Kusewa for his work which formed the backbone of the agronomic review of lupine. Appreciation also is extended to the Deputy Director of Research of the Kenya Agricultural Research Institute for permission to publish these results and to Mr. D.K. Muthoka, Director of National Agricultural Research Station, Kitale for his assistance logistically.

References

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de Souza, D.I.A. 1969. Legume nodulation and fixation studies in Kenya. East African Agricultural and Forestry Journal 34:299-305.

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Heath, M.E., Metcalfe, D.S. and Barnes, R.F. 1975. Forages. Iowa State University Press, Iowa.

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Poultney, R.G. 1963. A comparison of direct seeding and undersowing on establishment of grass, and the effect on the cover crop. East African Agriculture and Forestry Journal 29:26-30.

Savile, A.H. and Wright, W.A. 1958. Notes on Kenya Agriculture III, Oil seeds, pulses, legumes and root crops. East African Agriculture and Forestry Journal 24:1-9.

Wanjala, B.W. 1979. An introduction to lupin cultivation. Kenya Farmer. January. English Press, Nairobi. p. 17.

Wanjala, B.W., Wandera, J.L., Muyekho, F.N. and Kamau, J.N. 1983. Annual Report. National Agricultural Research Station, Kitale.