Are Chilean Pasture Seed End-Users Adopting New Species? Trends and Joinpoint Regression Analysis of the Last 19 Years of Seed Imports

: Pastures are important for the agricultural sector as forage, recreational and sports systems. The Chilean pasture seed market is highly dependent on introduced genetics; however, the effect of climate change and market conditions can modify pasture options. The objective of this study was to quantify changes of the pasture seeds sown by Chilean end-users, as metric tons (Mt) or proportion of the total (PT), based on 19 years of imported seed. The Mann–Kendall test and joinpoint regression analysis were used to estimate the overall trends and the average annual percent change (AAPC) for the whole period, respectively. The total imported Mt had an increasing trend and AAPC (+5.7%), wherein a large PT corresponded to ryegrasses ( Lolium spp.) (0.681), with increasing trends for Mt and PT. Clovers ( Trifolium spp.) had decreasing trends and AAPC ( − 2.9% for Mt and − 9.6% for PT). For PT, the main species was perennial ryegrass ( L. perenne L.) (0.357), with increasing trends for Mt. As Mt, a positive AAPC was found for plantain ( P. lanceolata L.) (+17.4%) and chicory ( C. intybus L.) (+63.2%). Over a period of 19 years, based on Mt but not PT, Chilean end-users have been adopting new pasture species with a decreasing use of Trifolium spp.


Introduction
Grassland systems are one of the most important ecosystems in terms of providing feed to ruminants for milk and beef production [1]. It is estimated that at the global level, grasslands account for nearly 50% of feed use in livestock systems [2], 80% of the world's cow milk production and 70% of the world s beef and veal produced in temperate grasslands [3]. In addition to the importance of temperate pastures in bovine diets, some species are highly adapted to close cutting because they have a high recuperative growth capacity after damage and biomass removal, making them suitable for lawns and sports fields [4]. In this usage, the pasture surface is called turfgrass and has many attributes; it can be used as an ideal playing, walking and seating surface and also helps to prevent erosion of the soil by water and wind [5]. Both sectors (animal production and recreational sports) use pasture seeds to reach some of their objectives.
At the global level, the pasture and forage seed market has increased by 50% to 60% in volume since 1990, mainly due to the increased demand of seed for turf [6]. According to [7], the forage and turf world seed production of 19 selected species was 846,573 metric tons (Mt), composed of 30.4% perennial ryegrass (Lolium perenne L.), 20.5% Italian and Westerwolths ryegrasses (Lolium multiflorum Lam.) and 19.3% tall fescue (Festuca arundinacea Schreb.). Indeed, 10 years of data from the European Union (EU-27) indicate that grasses account for 92% of pasture seed production [8].
grazing or turfgrass regimes. The authors use the term related turfgrass to include some species of the genera Lolium and Festuca spp. that are recognized as having a dual purpose: forage and amenity [28,29]. Brassicas, cereals, lupine, vicia, sorghum and specific turf-type species were not the focus of this article. Verified import data were first classified into six groups: Lolium spp., Festuca spp., Trifolium spp., Medicago spp., other pastures and the not determined (ND) group. The ND group was reported without a clear classification, such as seed blends of different species or inconsistency in their names, but related to the above groups.

Statistical Analysis
A descriptive analysis of the proportion of mean annual imports of the 19-year period was performed, and the proportion of pastures related to the total seed imports was calculated.
Two analyses were performed to study trends in the Chilean pasture seed market. Firstly, we examined the trend over the 19-year period by means of the Mann-Kendall test for non-autocorrelated data, or the modified Mann-Kendall test for autocorrelated data [30]. As these tests identify only monotonic trends (increasing, decreasing or no trend), and not the changes over time, the data were analyzed using a joinpoint (turningpoint) regression analysis [31]. Joinpoint regression has been used to analyze trends in environmental issues [32], sales trends [33], ecological risk assessment [34], bibliometric analysis [35], but mainly in cancer surveillance [36]. This analysis determines when a significant change in trends is present, assessing the annual percent change (APC) between trend points and the year when a change in the trend is produced. A number of joinpoints are selected using the Bonferroni correction for multiple testing, and the tests of significance use a Monte Carlo permutation method [37]. For each group and species, the average annual percent change (AAPC) is calculated for the whole period. If no change in trends is observed in the joinpoint analysis, the AAPC value is identical to the APC.
Both Mann-Kendall tests and joinpoint regression analyses were used in two data sets, imported seed in metric tons (Mt) and the proportion of each group/species in relation to the total imported seed (PT). A p-value < 0.05 was considered statistically significant. For years with no import data, the time-point was omitted [38]. For Mann-Kendall tests, R [39] and PAST [40] software were used. For APC and AAPC, the Joinpoint Regression software was used [37].  (Table 1), an increasing trend was observed over the 19-year period and a significant AAPC of +5.7% (Table 2). Despite this, the joinpoint regression analysis for the total imported seed ( Figure 2a) indicates a change in trend in year 2015, with a significant APC (+10.6%) from year 2001 to 2015, decreasing afterwards.

Total Imported Seed
Expressed as a proportion of the 19-year period mean (2698 Mt), the change in total imported seed between 2001 and 2015 ranged from −0.51 to +1.00, with positive proportions in year 2008 and from year 2010 onwards. After the peak in year 2015, the proportion of the mean annual imports decreased to nearly zero (+0.05) in 2019 ( Figure 1). In terms of imported Mt of pastures (Table 1), an increasing trend was observed over the 19-year period and a significant AAPC of +5.7% (Table 2). Despite this, the joinpoint regression analysis for the total imported seed ( Figure 2a

Genus and Group Trends and Changes
In the 19-year period, a large PT corresponded to the genus Lolium spp.  (Table 1).
In the period as a whole for Mt, Lolium spp., Festuca spp., and the other pastures group showed an increasing trend, but the latter had only a significant AAPC of +6.1% (Table 2). Lolium and Festuca spp. have had an increasing trend as a PT over the years, and Festuca spp. only, a significant AAPC of +2.4% ( Table 2). The remaining genera have no trends for Mt and PT as in the genus Medicago spp., or a decreasing trend in Mt and PT as in the genus Trifolium spp. (Table 2). Both legumes have a significant AAPC as PT, −4.4% and −9.6%, respectively ( Table 2).
Within the period for Mt, a change in trend was observed for Lolium spp.   3 Average annual percent change. 4 Significantly different from zero at alpha = 0.05. The species L. rigidum, M. truncatula, T. incarnatum, T. ambiguum and P. pratense, as well as spaces with no data indicate no sufficient data to perform the analysis.

Species Trends and Changes
For PT, the main reported species over the period was L. perenne (0.357), accounting for more than one-third of all documented species, representing 52.4% of the genus Lolium spp., followed by L. multiflorum (0.132), F. arundinacea (0.107), and the legumes M. sativa (0.085), T. repens (0.036) and T. subterraneum (0.011) ( Table 3). In addition, there was an important proportion of ND seeds belonging to the genus Lolium spp. (0.121). As a percentage, the ND data within Lolium and Festuca spp. accounts for 17.9% and 9.6%, respectively. This contrasts with the low proportion of data not determined that was found between groups: only 0.006 (Table 3). In the other pastures group, the most important species were D. glomerata and x Festulolium, which represent a PT of 0.030 and 0.014, respectively (Table 3). Other pasture species appear intermittently and represent <0.001 of the total, such as L. rigidum, M. truncatula, T. vesiculosum, T. incarnatum, T. ambiguum, P. pratense, Bromus spp. and Lotus spp., with no imported material of the last two in the last 6 and 11 years, respectively (Table 3).   In the entire period, the species L. perenne, L. multiflorum, L. x hybridum and F. arundinacea have an increasing trend in Mt but none with a significant AAPC (Table 2). Only the species L. multiflorum and F. arundinacea showed an increasing trend as PT over this period, and the latter a significant APC of +2.6% (Table 2). In relation to legume species, M. sativa is the most important forage legume as Mt and PT (Table 3), representing 99.0% of all species within the genus. No trend for Mt was found, but a decreasing trend for PT was found ( Table 2). The AAPC for Mt and for PT were not significant. The second-most important legume species in terms of seed imports was T. repens, representing 59.5% of Trifolium spp. For T. repens, no trend as imported Mt, but a decreasing trend as a PT was found in the 19-year period. Neither Mt or PT had a significant AAPC (Table 2). Similarly, T. subterraneum and T. alexandrinum had decreasing trends and a significant AAPC (−8.5% and −22.5%, respectively) as PT. The species T. fragiferum had a decreasing trend in Mt and PT, and the rest of the Trifolium spp. species have no trends in both types of analysis performed ( Table 2). From the other pastures group, only D. glomerata showed an increase in terms of Mt, with a significant AAPC of +6.6% ( Table 2). The forage herbs P. lanceolata and C. intybus have no trends but a significant AAPC (+17.4% and +63.2%, respectively) as Mt, and only C. intybus had an increasing trend as PT (Table 2).
When Mt import data were analyzed within the period, the joinpoint regression analysis indicates changes in the trends for L. perenne, L. multiflorum, L. x hybridum, F. arundinacea and T. repens

Overview of the Genus and Species Imported
In Chile, the amount of pasture seed use is small compared to worldwide usage. The pasture seed imported in 2007 represents less than 0.5% of the total world seed production [7]. Despite this, in Chile the pasture seed market has been dynamic in terms of imports with an increase of over 4000 Mt in the first 15 years of the period from 2001 to 2015. Mainly due to Lolium and Festuca spp. importations, both reflecting the increasing market as a component of forage and turf fields [28,29]. This overall figure is similar to the world seed production data [7], with a greater importance of grasses over legumes, and Lolium spp. over other genera [6].
Tendencies in imports of forage seed depend on multiple factors including the demand of seed by farmers, climatic factors that generate the need to sow pastures (drought, cold winters and others), and/or a high price of the animal products, mainly milk, leading to a higher investment in pasture establishment. If the US dollar exchange rate is favorable, the cost of imports is lower, seed production in Chile is less economically attractive and imports increase. International forage seed prices, alternative use of land, and profitability of cereals, all affect land use for Chilean forage seed production.
The import peak in the year 2015 could be due to higher pasture establishment due to the extreme drought event between January and March ( Figure S1). This, coupled with the high mean air temperature ( Figure S2), leads to an increase in the importations (Tables 1 and 2). The accumulated precipitation in those months was only 22 mm, extremely low compared with the 40-year mean rainfall of 142 mm. Another reason may be the low US dollar exchange rate that year, high international wheat prices and the national area sown with cereals (mainly wheat and oat) that reached a peak between the years 2014 and 2016, which all contributed to making import of pasture and turfgrass seed more attractive than producing it in Chile [41]. The increase from 2001 to 2015 was mainly in the Lolium spp. group followed by Festuca spp. (Table 1, Figure 2a). The species L. multiflorum showed the biggest increase in the years 2014 to 2016 (Table 3, Figure 2b) and this was due to the availability of seed for this species and the lower price (personal communication of seed industry).
The CIF prices (nominal values) over the years for the imports of the genera Lolium and Festuca spp. had the lowest values compared to Medicago spp., Trifolium spp. and the other pastures group (Figure S3), making them more available in terms of price for end-users.
The increasing trend of ND seed (as Mt) within Lolium and Festuca spp., and their significant AAPC (+7.9% and +8.7%, respectively), diminish the option to have a more specific value of the real amount of seed. Unfortunately, within Lolium and Festuca spp. data, there is not enough detail in terms of cultivars or use. A more detailed classification system is needed in order to have clear information about the intrinsic characteristics of each species, farmer reseeding activity and the intended use of the seed. For example, in a 10-year period in the Republic of Ireland, overall imports of grass seed increased to over 5000 t, but mainly due to a doubling of amenity grass seed imports, with seed usage of grasses and clovers in agriculture between 3000 and 3500 t [12]. This reflects the importance of a more detailed data collection to neither underestimate nor overestimate the real use of the seed, to calculate the surface that is (theoretically) reseeding each year and to identify how pasture end-users are facing the constant challenge in growing and maintaining pastures. This valuable information allowed the quantification of the decline in reseeding activity in a nearly 30-year study in Northern Ireland [12], a decline in the use of early maturing cultivars and a steady increase in tetraploid perennial ryegrasses in a 25-year survey [13].
Legume species have great potential for production in the Mediterranean region of central Chile, because of plant survival under low rainfall conditions and the possibility to extend the growing period [42,43], but the higher CIF prices (nominal values) compared with ryegrasses and fescues could affect the adoption of these legumes by farmers ( Figure S3). For instance, M. sativa is more tolerant of growth under limited water availability than a range of grasses, legumes and forage herbs species [44], and the persistence remains unchanged under different defoliation regimes [45]. This particular species has a strong Chilean seed production company that supplies an important amount of seed to farmers, masking the real use of this forage legume. Secondly, M. polymorpha does not show any trend (Table 2) and the PT is very low (Table 3). This species has good agronomic characteristics for Mediterranean conditions, and some cultivars were developed for sub-humid and humid Mediterranean zones [46].
For the Trifolium spp., the amount of seed imported may be a concern. It is the only group that showed a decrease in all parameters: Mt, PT and AAPC (−2.9% and −9.6% respectively). The species T. repens is by far the clover species with the largest amount of seed imports (Table 3). In 1999, data indicated that the clover import was approximately 271 Mt [20], but in the period from 2001 to 2019 the mean was 161 Mt (Table 1), with a continuous and significant decrease in importation (Table 2). From a grazing perspective, forage legumes have greater importance because of their high nutritional value in the ruminant diet and the ability to reduce N leaching by reducing the use of N fertilizers [17,47]. In terms of yield, there is an economically important advantage of the perennial ryegrasswhite clover mixture in high N treatments (225-325 kg N ha −1 year −1 ), as summarized in a series of multisite-year research [48]. Grass and white clover mixtures have the potential to increase milk production per cow and similar levels of overall milk production than only grass systems, but with less fertilizer inputs [49].
A focus on better grazing management to improve the persistency, yield and use of the Trifolium spp. species should be considered, and the benefits of reseeding white clover or red clover in an existing permanent pasture can be considerable in terms of dry matter and crude protein yield [50].
Other forage legumes in temperate regions are less used [15] and have only a small place in the Chilean market. The evaluation in terms of yield and persistence is used to improve the animal production systems both in the Mediterranean production areas [43,51] and temperate ecosystems [17], characterized globally by a low adoption of annual legumes by farmers [52]. The successful development, particularly in Australia, of mainly annual legumes [53] and the new phenological stage scales developed for T. subterraneum and T. alexandrinum could help improve agronomical practices and increase the use of these less adopted species [54]. To increase the forage legume options, the T. pratense breeding program of the Instituto de Investigaciones Agropecuarias (INIA-Chile) has been working in the last three decades to improve persistence and forage yield, releasing new improved cultivars [55].
In the other pastures group, D. glomerata was the most important. This species could see a systematic improvement after a complete phylogenetic analysis of the genus Dactylis spp. [56]. Another option for farmers is the use of the hybrid x Festulolium, which has appeared continuously since 2006, but without any trend. This hybrid is an alternative to those species that lack the quality and resilience of x Festulolium to biotic and abiotic stresses [57].
The characteristics of P. lanceolata and C. intybus of increased productivity during summer months [58] and the tolerance of hot and dry conditions over other common species [59] are desired features that farmers need in order to extend the grazing period, helping to increase the persistence of sown species and reducing weed ingress when forage herbs are included in the pasture mixture on sheep and beef systems [60] and increasing milk production as a part of multispecies swards [61]. The forage herb C. intybus is suggested as a potential alternative to F. arundinacea, D. glomerata and L. perenne under frequent heat and drought stress [62].

Chances of Adopting New Species
There is a world tendency towards the use of specialized and proprietary cultivars [6], but market prices and volumes are the primary factors that determine the success of a new cultivar [63]. The development of cultivars adapted to abiotic stress is necessary, and is one of the issues that the seed industry must address with the climate change conditions [64].
Chile has a free market-oriented economy, and is usually in line with the world market. The Chilean market depends on international prices and quantities available on the market and internal dynamics such as prices of animal products and climatic conditions affecting the demand for forage seed. Moreover, the Chilean market is very dynamic in terms of available cultivars due to the few legal requirements when introducing a new variety into the market. In fact, the Chilean legal system allows the introduction of new cultivars of known species to the market without the requirement of performing a prior agronomic evaluation. This has at least three consequences. First, from the market standpoint there is a rapid change in available cultivars with less emphasis on its agronomic value and more on the seed price. Second, from the production point of view, there are no official data available regarding the agronomic value of the cultivars, so farmers have no possibility of choosing the cultivars better adapted to their environment [55]. Third, it is difficult for national breeding programs to compete in a market that works like a commodity market rather than as a specialized one.
Chile has good soil and climatic conditions and dry summer for seed production. In the forage and turf groups, Chile has not developed a competitive industry, due to the low and variable international price for forage and turfgrass seeds. These have not allowed the competitive development, in a medium-term perspective, of the required know-how for the industry to compete. To guarantee seeds of the best adapted cultivars to local conditions, a successful pasture seed industry must be developed [52].
In the last 60 years, few Chilean forage cultivars have been developed and reached the market. Only T. pratense has been important for both national and export markets [55]. The first two cultivars of the native grass Bromus valdivianus (Bromino-INIA and Bronco-INIA) that were developed in the last decade are only just now slowly getting into the market as "new" species [65]. Therefore, most of the forage and turf seed is imported and the amount of imported seed or national production depends on multiple factors (dollar change rate, international seed prices, competitive crop prices such as cereals, and others).
Local research on new imported pasture species is needed. In addition, introduced and local cultivars must be evaluated under abiotic stress conditions to measure their potential impact on yield and, in the case of turfgrass varieties, ornamental features. Forage breeding, from the range that comprises Mediterranean to Nordic areas, should improve plant strategies to face abiotic stresses and optimize growth and phenology to new seasonal changes [25]. Under these conditions, the introduction and evaluation of species or cultivars to extend the production period and increase productivity under rain-fed environments [43] is a first strategy to increase livestock productivity. For those with irrigation, strategies to improve water productivity to optimize forage production are documented [66,67].

Implications for the Agricultural Policies
The official source of data, which come from the Office of Agricultural Studies and Policies (ODEPA) with information from the National Customs Services, is detailed in terms of genus, but in many cases the data are incomplete in terms of species, cultivars or the intended use of the seed (forage or turfgrass). In some cases, there is no clear description of the species belonging to a specific genus (mean percentage of ND data is 17.9% in Lolium spp.). For dual-purpose species, identifying the cultivar name is the way to know the final use [8]. This implies that a more exact classification system should be implemented by the Office of Agricultural Studies and Policies (ODEPA) and the National Custom Services once the seed arrives at the national territory in order to specify data in terms of cultivar, blend name and the intended use of seed. These will allow a continuous quantification of the pasture seed imports at a country level, the estimation of the theoretical surface and tendencies at the species level.

Conclusions
The results show that over the last 19 years, pasture seed imports have an increasing trend and positive annual changes, largely dominated by the genera Lolium and Festuca spp., and L. perenne at the species level. However, the level of not determined data and the lack of cultivar information and/or the intended use of seed within each of both genera limits a more precise analysis. The genus Trifolium spp. and its main species (T. repens, T. subterraneum and T. alexandrinum) have a decreasing trend over time as a proportion of the total. Only D. glomerata, P. lanceolata and C. intybus showed some increasing trends. Focused on the results, Chilean end-users have been increasing the use of Lolium and Festuca spp., decreasing the use of Trifolium spp. and slowly adopting some new pasture species. The analysis of these tendencies is important to orientate plant breeding programs, research and extension to the farmers; however, more detailed data at the species and cultivar levels are needed to perform a more precise analysis. This would allow the design of agricultural policies to cope with climate change conditions and the prioritization of breeding and research in the agronomy of new species to enhance pasture and turfgrass systems.