INVESTIGATION OF AGRONOMIC IMPORTANT CHARACTERISTICS OF CULTIVARS AND POPULATIONS OF WHITE CLOVER (TRIFOLIUM REPENS L.) IN AGROECOLOGICAL CONDITIONS OF SERBIA - Z. Lugic, S. Ignjatovic, D. Lazarevic and J. Radovic

Agricultural Research Institute “Serbia”, Belgrade Center for Forage Crops, Trg rasinskih partizana 50, 37000 Krusevac, Yugoslavia

SUMMARY

In agroecological conditions of Serbia (temperate continental climate) fourteen genotypes of white clover were examined on agronomy important characteristics: green mass (GM) yield per plant, plant height, diameter of sward, leaf size, crude protein (CP) content and crude cellulose (CC) content. The foreign cultivars Arcadia, Dubrava, Olwen and domestic selected population KS-1 had the highest GM yield per plant, while natural unselected population nos. 13 and 14 were the lowest. The highest plant height was in the first cut of the second year and cultivars Arcadia, KS-33 and Medunnai were the highest. The cultivar Pastevac, selected population KS-1 and unselected population Lomnica had the biggest diameter of sward in the third cut of the second year, while the swards of unselected population nos. 13 and 14 were the slowest in spreading. The natural unselected populations 13 and 14 had the smallest leaf size. CP content was greatly affected by genotype and was the highest in cultivar Dubrava. Unselected population nos. 13 and 14 and cultivars Merwi, Olwen and KS-33 were the highest in CC in agroecological conditions of Serbia and the cultivars Milka, Pastevac, Dubrava and KS-1 had low CC content. These results indicate that cultivars Merwi, Arcadia, Dubrava and KS-1 could be successfully cultivated in the agroecological conditions of Serbia.

Keywords: agronomic characteristics, cultivar, population, single plant, white clover

INTRODUCTION

The total area of pastures and grasslands in Serbia is about 1 361 000 ha and that represent 21.3 percent of total agricultural area. More than 80 percent of this area are in hilly and mountainous districts at 400 to 1 200 m above sea level. The possibility of forage production in these conditions and therefore the importance of white clover is great (Prvulovic et al. 1990). The contribution of white clover in forage production is minor, although there are good edaf and climate conditions. The main cause is that Serbia, until 1995 did not have its own cultivar. A white clover breeding programme was recently established (ten years ago). The natural white clover populations in Serbia had positive morphological performances and could be included, besides introduced cultivars in the breeding programmes (Lugic et al., 1996). According to Oyen et al. (1991) and Evans and Wiliams (1986), local populations and domestic cultivars were superior than other genotypes in its own climate conditions. The aim of this investigation was to evaluate agronomic performances of some foreign cultivars, one domestic and some natural unselected populations of white clover in agroecological conditions of Serbia.

MATERIALS AND METHODS

The experiment included nine foreign cultivars, one selected population (KS-1) and three natural populations - Lomnica, Rasadnik and Kopaonik. Domestic cultivar KS-33 was considered as a standard. Seeds were scarified with fine sandpaper and sown in jiffy-pots in spring 1996. Thirty plants per genotype were sown. In the stage with two to three leaves, plants were planted in the field on 1.5 x 1.5 m distance. Plant height, green mass (GM) yield per plant (g), diameter of sward (cm) and leaf size (cm) were monitored during the first and second year. Crude protein (CP) content and crude cellulose (CC) content were determined on the samples from the first cut of the second year. Differences between the genotypes for all examined parameters were tested by T-test.

Serbia has temperate continental to continental climate with very humid periods during vegetation (Table 1).

RESULTS

In the first year plant growth and development of all genotypes was slow as a result of low amount of precipitation and high temperatures during vegetation, so we have only one cut (Table 2).

In the first year, there were significant differences between genotypes for plant height, diameter of sward, leaf size and GM yield per plant. Cultivar Arcadia had the highest GM yield per plant (231.5 g) and plant height (22.4 cm), while cv Olwen had the highest diameter of sward (52.4 cm). Natural wild populations Rasadnik and Kopaonik was the lowest in plant height (12.9 and 12.5 cm, respectively).

In the second year (Table 3), due to high level of precipitation, plant development was normal and we had three harvests. The greatest mean value for GM yield per plant was in the first cut ranged from 471.4 g (cv No.14) to 1 445.3 g (cv No.5). The highest GM yield per plant in all three cuts had, as in the first year, cv Arcadia (cv No. 5), followed by cv Olwen (No. 6). Cultivar Arcadia had the plants weight even 2 950 g green mass and plant height was about 40 cm. Cultivars nos. 2, 3, 4, 5, 6 and selected population no. 10 had higher GM yield per plant than standard, while wild unselected population nos. 13 and 14 and cultivar no. 1 were significantly lower then standard.

For all genotypes, the greatest plant height was in the first cut which ranged from 26.7 (cv. no. 14) to 34.2 cm (cv. no. 5). The lowest plant height was in second cut (6.9-17.7 cm).

In the second year the single plants of all genotypes developed rapidly, so some of them increased its sward from 40 cm in the first year, to over 120 cm in the third cut of the second year. Selected population KS-1, unselected population no. 12 and cv Pastevac had the largest diameter of sward in the third cut of 1997 (96.7, 93.2 and 90.1 cm, respectively) while the swards of unselected population nos. 13 and 14 were the slowest in spreading (from 58.5 and 53.0 in the first to 79.5 and 72.4 cm in third cut, respectively).

There were great differences between cultivars in CP content. Cultivar no. 7 was the highest in CP, but the population nos. 13 and 14 were significantly lower then standard. CF was lower in cultivars nos. 2, 7, 9 and 10 than standard and higher or the same as standard in population nos. 13 and 14.

Table 1. Distribution and amount of precipitation (in mm) in Krusevac during 1996-1997.

Table 2. Mean values and significance of differences between genotypes for examined parameters in the first year.

Table 3. Mean values and significance of differences between genotypes for examined parameters in the second year.

DISCUSSION

Natural populations had smaller leaf size and lower plant height compared to all others, while there were no significant differences for diameter of sward and GM yield per plant. Rapid spreading of sward and leaf size are assumed as a good predictor of genotype competitiveness (Camlin, 1981). Among natural unselected populations, Lomnica (no. 13) was the highest in diameter of sward in all three cuts.

Diameter of sward increased from first cut of 1996 to third cut of 1997 as well as GM yield per plant for all genotypes. The mean values for this parameter show that the diameter of sward increased for about 20 cm from cut to cut.

Crude cellulose content shows large differences between the genotypes (ranged from 144.5 to 232.8 g kg^-1). Differences between the genotypes for these parameters could be affected by different phenophases at harvest time. All plants of all genotypes were harvested the same day, but some of them, especially natural populations, had earlier flowering compared to other genotypes.

CONCLUSION

In agricultural conditions of Serbia, due to a high precipitation during summer, a high green mass yield was achieved in 1997. Cultivar nos. 2, 3, 4, 5, 6 and 10 were significantly higher for GM yield per plant than standard, while unselected population nos. 13 and 14 were poorer.

Plant height had great fluctuation during cuts and was the highest in the first cut of the second year.

All genotypes increased in diameter of sward from cut to cut and unselected population no. 12 was the greatest at the end of the second year.

Leaf size was also affected by genotype and was the lowest in domestic unselected population nos. 13 and 14.

The chemical composition was affected by genotype and by plants phenophase also at the moment of harvesting.

REFERENCES

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