VARIETAL CHANGES IN TWO FINNISH ALSIKE CLOVER VARIETIES GROWN FOR SEED IN THE USA

Abstract. Two Finnish alsike clover varieties, diploid Tammisto and tetraploid Iso, were grown for seed at different locations in the USA for several successive generations. The seed lots were tested in single-plant and forage production trials in Finland to reveal possible varietal changes caused by producing seed in foreign environments. Many of the Tammisto alsike lots produced in the USA had more early-type plants than the Finnish basic seed. In contrast the USAgrown Iso lots which differed from the basic seed had lower average growth type indices and fewer flowering plants. Increase in earliness was supposed to result from efficient pollination during early, sparse flowering, decrease in earliness from the fact that alsike clover is a species especially prone toshedding its seeds as soon as they mature. In spaced-plant tests many of the USA lots produced progenies with less winterhardiness than those from the basic seed lot. The poorest overwintering was recorded for the lots from the southern locations. There were no appreciable differences between the four production localities in the United States in terms of other characteristics of the two varieties. With successive generations of increase no progressive varietal changes were found to occur. Seed lots harvested from the same plot for two or more years did not differ from each other. Forage yield trials comparing the most advanced generation seed lots from the USA with basic seed did not reveal any consistently significant differences.

duction problems in Sweden.In the 1960's seed increase experiments with Tammisto and Iso were started in the states of Washington, California and Arizona, USA, to determine whether seed production was practicable in foreign countries for export to Finland.Preli- minary experiments had been carried out in the USA and evaluated in trials in Finland before (Valle and Garrison 1959).Producing seed of a variety under conditions differing from those in its region of origin may induce changes which adversely affect its agricultural value where it is grown for forage.Thus, in addition to the experimental seed increases of Tammisto and Iso alsike clovers in the USA, a number ofevaluation and forage production trials were initiated in Finland.This paper presents results of single-plant evaluation trials and forage production tests carried out with Tammisto and Iso alsike clover seed produced in the USA at the Department of Plant Husbandry of Agricultural Research Centre, Tikkurila, the Department of Plant Husbandry of the University of Helsinki, Experi- mental Farm Viik, and the Experimental Farm Länsi-Hahkiala, Hauho, in the years 1964-70.

Materials and methods
Seed production in the USA.Seed of Finnish alsike clover was produced at four different locations in the USA; Prosser, Wash. (lat.46°15' N), Tehachapi (35°8'N) and Shafter (35°23' N), Cal., and Tucson, Ariz.(32°30' N).Table 1 presentsdaylength and weather data for these locations and shows clearly the great basic differences between the environmental conditions in Tucson and Shafter on one hand and Finland on the other.Tehachapi, situated on approximately the same latitude as Shafter but in a mountain valley (elevation 1200 m above sea level; Shafter 110 m) has a climate more closely re- sembling that of Prosser, Washington.At the four experimental locations in the USA alsike clover seed was produced under irrigation.Consequently the serious hazard of excessive moisture during the period of seed ripening and harvest, all too familiar in Finland, seldom occurs at these American locations.
Specified data on the USA productions of Finnish alsike clover seed are presented in Table 2.At Prosser, the average seed plot size was 500 m 2, in Shafter, Tehachapi and Tucson 120-200 m 2. The seed increase plots were sown either in spring or fall.From spring-sown plots the first seed crop was usually harvested in the fall of the planting year.
The plots were harvested for seed in two years.One seed crop a year was generally taken; the third-generation Tammisto in Tucson was harvested twice in both of the two crop years (main crop harvest in July and aftermath harvest in early October).All the Tucson plantings yielded very little seed; the aftermath harvests only gave 12 and 18 kg/ha.Some fairly satisfactory seed yields of both Tammisto and Iso were obtained at Shafter and Tehachapi although even there most yields were poor.Prosser was found the most suitable location for production of alsike clover seed.Seed set observations on Tammisto and Iso in the USA (Table 3) revealed no variation due to location of production.For each variety the average numbers of florets and seeds per flower head were approximately the same at all locations.There were no significant differences in numbers of flower heads per area unit.
Evaluation in Finland.Evaluation trials with US-grown Tammisto and Iso alsike clover seed lots were carried out in Finland from 1963 to 1970 except for 1965.
The present paper reports on the results of the years 1964, and 1968-70.Trials in these years included the 3rd and 4th-generation productions as well as one Ist and 2nd-genera- tion lot for each variety and location.In 1964 the USA grown lots were compared with the original Finnish basic lots.Since the latter were produced as early as 1957 (Tammisto) and 1959 (Iso), they were replaced in the later trials (1968-69) by Finnish first-generation lots grown from the basic lots in 1964 and 1965.Separate evaluation trials showed the first-generation Finnish lots to be similar in characteristics to the original basic seed.
In 1964 the trials were situated at the Department of Plant Husbandry, Tikkurila (60°18' N), in 1968-70 on the University Farm Viik (60°13' N).The 1964 trials were established by sowing the seed directly to the field in rows 50 cm apart and subsequently thinning the stands to 35 cm plant distances within the row.For the 1968-69 trials seed was sown in flats in greenhouse in early April.The seedlings were transplanted to plastic »multipot» growing trays (pot diameter 35 mm) when about one month old and to the field in late May-early June.Plant distances were 50 X 50 cm.In setting up the trials a randomized block design was used with four replications in 1964 and 1968, and six in 1969.Total numbers of plants per seed lot in the three years were 256, 176 and 144, respectively.
Several growth type observations were made on single plants during the first summer following planting.The evaluation scale used for red clover in similar trials by Valle   and Garrison (1965) was modified slightly for alsike clover.It included the following plant type categories; Harvest year 0 = year of planting; 1 = Ist year following planting year; 2 = 2nd year following planting year.*) Second harvest in the same year. 1 = Rosette only 2a = Tiller formation just begun (1 internode) 2 = Rosette with tillers with 2 internodes 3 = Rosette with tillers with 3or more internodes 4a = Large rosette, stems with flower buds 4 = Large rosette, stems with open flowers 5a = Small rosette, stems with flower buds 5 = Small rosette, stems with open flowers 6a = No rosette, stems with flower buds 6 = No rosette, stems with open flowers.Individual plant type observations were made on different dates during the first sum- mer.An average growth type figure was calculated for each lot for each observation date.Also the percentages of flowering plants were determined.Only results from the obser- vation date that most clearly show differences between seed lots are given in Tables 4-9.The earlier observations were more definitive.In the later ones with increasing growth and more abundant flowering, differences between the lots tended to disappear.In 1968 the plants were cut in late summer and their individual fresh weights as well as numbers of stems and flower heads per plant were determined.The size of each individual leaf rosette was assessed about one month later to show the aftermath growth.The 1968 trial was eva- luated for winter survival in the spring of 1969; the date of beginning of flowering was subsequently recorded for each plant separately.The 1969 trial was sprayed with PCNB several times during the first fall in order to secure successful!overwintering.The resulting high rate of survival made it possible to carry out accurate flowering observations in the second season.
Forage production trials, consisting of the Finnish standard and three seed lots from the USA, were established for the two alsike clover varieties in 1968.The locations for these trials were University Farm Viik (60°13' N) and Experimental Farm Länsi-Hah- kiala at Hauho (61 °9' N).Seeds were drill-sown in rows spaced 15 cm apart under a nurse crop ofbarley at Viik and oats at Länsi-Hahkiala.Plot size was 10 m 2. There were 6 replications at Viik and 4 at Länsi-Hahkiala.The trials were harvested twice in each of two years following the planting year.Fresh forage yields were weighed and tons/ha calcu- lated.Dry matter and crude protein contents were determined for one or two replications.Winter survival was also recorded.
The experimental data were statistically analysed and significant differences between means determined by Duncan's multiple range test.

Results
The results of the various years were surprisingly different in Tammisto alsike clover.
In the 1964 trials with first and second-generation lots from Prosser, Tehachapi and Tucson most of the USA lots showed higher proportions of early-type plants with small leaf rosette than the basic seed lot (Table 4).In later trials, on the other hand, the growth type means for most of the lots produced in the USA did not differ significantly from that for the basic lot.In the 1968 trial (Table 5) the USA lots had smaller means than the basic lot indicating later flowering types.However, in the 1969 trial (Table 6) the growth type Means followed by the same letter within trial are not different at the 5 % level of significance.means for the USA lots were generally larger than the mean for the basic lot.In the tetraploid Iso no changes in growth characteristics could be seen in the first two USA gene- rations (Table 7) and significant differences from the basic seed were still quite rare in the  later generations (Tables 8 and 9).It is worth noting, however, that while many of the USA lots of diploid Tammisto alsike showed a slight tendency towards higher growth type indices and earlier flowering as compared to the basic seed, the tendency for the tetraploid Iso was the reverse, towards lower growth types and scarcer flowering.
Seed sources within either variety did not show any appreciable variation in fresh weight per plant (Tables 5 and 8).Differences in numbers of stems and flower heads were likewise small and insignificant.
Aftermath growth of the USA lots was, with a few exceptions, similar to that of the Finnish lots.Nevertheless the spaced plants of many USA lots overwintered significantly poorer than the Finnish ones (Tables 5 and 8).The Tammisto and Iso alsike lots from Shafter suffered the worst winter damages.Unfortunately no overwintering data are avail- able for the Tammisto lots grown in Tucson where climatic conditions provided more se- vere selection pressures than those at Shafter.There was some discrepancy in Tammisto alsike between the growth type figures of the first summer and the beginning of flowering in the second (Table 6).Many lots for which larger growth type means had been recorded in the planting year started their T a b l e second-year flowering slightly later than the basic lot.Differences in flowering time were not significant, however.In the Iso alsike there was better agreement between the first and second-year observations (Table 9).
In the forage trials the USA-grown Tammisto lots showed only slightly poorer over- wintering; in Iso there were practically no differences at all from the basic seed (Tables 10-11).Some significant differences occurred in fresh yields at P = 5 %.The results indicate that first cut forage yields for the USA-grown lots of diploid Tammisto were slightly smaller than for the basic lot.In the second cut the relative yields of the USA lots were larger than in the first cut, which may reflect their more rapid regrowth capacity due to earliness.
Dry matter percentages for the USA lots were as high as those for the basic lots.In crude protein no significant differences were found.Due to the low number of analyses made, statistical treatment of dry matter and crude protein data was not possible.

Discussion
Since the Tammisto variety of red clover was found to incur an apparent shift towards earliness when grown for seed in the USA (Valle and Garrison 1965), the same was expected of alsike clover.Preliminary experiments with Tammisto alsike showed that some decrease in the proportions of early plants occurred particularly when seed was produced at southern latitudes (Valle and Garrison 1959).The present study also revealed lower than normal growth type indices for some of the USA lots of Tammisto alsike and most USA lots of Iso.Yet many Tammisto lots also showed a shift towards earliness.This probably was due to the more profuse flowering of the early-type plants as well as to the fact that in a sparsely-flowering stand pollination was especially efficient, resulting in a higher than average seed set for the early plants.One of the factors inducing lateness in alsike clover may be the inclination of the species to shed its seeds soon after their matu- ration.If the period of flowering and seed ripening is unduly prolonged or harvest delayed due to unfavourable weather conditions, most of the earliest matured seeds will fall off the heads before harvest and the crop thus will consist mainly of seed produced by the late- flowering plants.
The changes in earliness were, however, so small that they do not affect the agronomic value of the seed lots in forage production in Finland.
With proceeding generations there were no progressive, accumulative changes.Neither did the trials reveal any differences between seed crops harvested in different years from the same field.
The present experimental results show only slight differences between the alsike lots from the different USA localities.The Iso, being a tetraploid variety less prone to genetic shifts than the diploid Tammisto, showed no growth type changes whatsoever due to location of production.In Tammisto, significant differences from the basic seed in terms of earliness were more common among lots produced at the southern locations (Shafter, Tehachapi, Tucson) than among lots from the northern site (Prosser).
Overwintering observations on both varieties showed that seed production in Shafter (no data from the Tucson lots) had the most detrimental effects.The decrease in winter survival was, however, quite small in the seed lots produced at the northernmost and high elevation locations, Prosser, Wash., and Tehachapi, Cal., respectively.Therefore seed produced in the USA for export to Finland should be grown in the north or at high ele- vations with cool temperatures.
Red and alsike clover varieties with early and profuse flowering have been found the most susceptible to winter injury (Smith 1957, 1963; Therrien and Smith 1960).Yet in the present trials the earliest USA lots of Iso alsike overwintered best.It should be noted, however, that the shift in Iso alsike clover was towards slightly later plant development.
The earliest USA Iso lots, which overwintered best, did in fact resemble the Finnish basic seed more closely than did the Shafter lots which according to the growth type observations were latest of all but nevertheless showed the poorest winter survival.

Table 2 .
Number of seed lots, harvest year and seed yield kg/ha of Tammisto and Iso alsike clover produced in the USA. *)

Table 3 . Seed yield components of Tammisto and Iso alsike clover seed grown in the USA.
Means followed by the same letter are not different at the 5 % level of significance.

Table 4 .
Results from spaced-plant evaluation trials with Tammisto alsike clover, 1964.Trials established in 1964.Means followed by the same letter within trial are not different at the 5 % level of significance.

Table 6 .
Results from spaced-plant evaluation trial with Tammisto alsikeclover, 1969 and 1970.Trial  established in 1969.Early harvest 2) = Late harvest Means followed by the same letter are not different at the 5 % level of significance.

Table 7 .
Results from spaced-plant evaluation trial with Iso alsike clover, 1964.Trial established in 1964.Means followed by the same letter are not different at the 5 % level of significance.

Table 8 .
Results from spaced-plant evaluation trial with Iso alsikeclover, 1968 and 1969.Trial established in 1968.Means followed by the same letter are not different at the 5 % level of significance.

Table 9 .
Results from spaced-plant evaluation trial with Iso alsikeclover, 1969 and 1970.Means followed by the same letter are not different at the 5 % level of significance.