Introduction

The improved seeds are those that come from the application of traditional techniques of genetic improvement include the identification, selection and multiplication through the years of many generations of outstanding genotypes, in order to obtain plants showing characters of interest are higher yield, tolerance to frost, drought, pests and diseases; as well as other attributes such as precocity and adaptability to conditions current and future different environments (^{Besnier, 1989}).

The importance of the use of improved seeds is that being an innovation, your goal is to create value for farmers, improving their competitiveness and profitability by increasing performance. Another way to create value is to meet food demand, and the use of improved seeds have impact on food security of households, especially the poorest, allowing meet the required amount of food because the surpluses generated increase per capita consumption (^{Shiferaw et al., 2014}; ^{Bezu et al., 2014}).

The maize is the most important crop in Mexico, in economic, cultural and food terms. Oaxaca is the fourth state that most agricultural area devoted to this crop with 601 000 179 ha^-1, same that produced 694 thousand 554 tons of maize, with average yields of 1.22 t ha^-1 during the agricultural year 2011 (^{SIAP, 2013}). The state has a production deficit of 180 thousand tons (^{Gobierno del estado de Oaxaca, 2013}), so the latest government administrations have raised the state achieve self-sufficiency in the supply of corn as a strategy. Therefore, as part of public policy it has included the development and introduction of technologies that increase the current yield of corn (^{Gobierno del estado de Oaxaca-Banco Mundial, 2012}) and improved seeds are an option to do so.

In this context, in 2012 the Oaxaca state government first implemented the State Program Certified Seed Corn. The program was to provide corn growers certified improved seed for free, which meant 12 thousand 350 bags of 20 kilograms each, for a total of 247 tons of seed to plant and produce corn consumption in the regions of Papaloapan Basin, Central Valley, Costa, Mixteca, Cañada and Isthmus.

Despite the efforts, only 8% of the maize area uses these seeds, which is considered low compared to other states in southeastern Mexico, such as Chiapas with 28% and Guerrero to 57% (^{SIAP, 2012}). The low adoption of improved seeds is attributed to limitations for dissemination, environmental adaptation and cultural and gastronomic aspects that do not meet expectations and customs of farmers. In addition to this, there is a more complete causal complex that accounts for the fact that farmers are not using improved seeds. This complex has not been sufficiently studied in Mexico and even less in a state with diverse characteristics and particular at the same time as it is Oaxaca.

Normally, farmers adopt a technology if they expect this contributes reach your goals whether economic, social or environmental. The perception of farmers towards risk and their attitude towards it, play a decisive role in the decision making process of peasant units for the adoption of technological innovations. The literature refers to the uncertainty generated in farmers associated with the perceived risks in several areas. On the one hand, there is the availability of physical and financial resources available; and other aspects of expected return with the use of new technology. And the risk and uncertainty of grain prices on the market; the personal characteristics of the farmer in terms of partial or total change provision.

Thus, as to the personal characteristics of the farmer, previous studies mentioned that age influences positively on the adoption, as farmers have extensive experience and agricultural knowledge that allow them to evaluate information technology and appreciate the advantages offered them (^{Mignouna et al., 2011}). As regards schooling, farmers with more years of schooling have greater ability to process information and seek appropriate production technologies restrictions than those with a lower education level (^{Mariano et al., 2012}).

With regard to the availability of physical and financial resources, the total surface reflecting household wealth is an indicator of the ability of farmers to take more risks and be willing to use improved maize seeds (^{Lunduka et al., 2012}). That is, the larger the area sown with corn higher are the chances of adoption of improved seed (^{Feleke and Zegeye, 2006}). According to ^{Ouma and De Groote (2011)}; ^{Abebe et al. (2013)} access to credit is significant for the adoption of improved seeds. Farmers who have access to credit, can buy improved maize seeds and other inputs (^{Paudel and Matsuoka, 2008}).

Expected profitability aspects with regard to achieving satisfactory results with the use of new technology, have to do with performance. According to ^{Matuschke and Qaim (2009)}, the probability increases to adopt improved seeds as a farmer perceives that its performance potential is higher than the existing premises. In addition, when farmers themselves experience an increase in performance with use, they are more likely to continue it to consolidate adoption (^{Mignouna et al., 2011}). Consider the fate of maize production and the structure and functioning of markets is crucial for the adoption of improved seeds. ^{Chianu et al. (2007)} mentions that ready access to markets, promotes agricultural intensification process as it ensures that production is marketed with reasonable profits, a key factor in the decision of farmers to adopt improved maize or not.

In addition to the factors explaining the adoption of improved seeds, cultivation practices are associated with this use. ^{Tura et al., (2010)} indicate that the adoption of a component of the technology package increases the likelihood that farmers use other essential components there of longer. Although improved seeds themselves contribute to increased productivity, their use should be complemented with the practice of other innovations and use of complementary inputs that allow them to express their genetic potential.

Water availability is an aspect that farmers consider for its decision to adopt improved seeds (^{Zavale et al., 2005}). Access to adequate irrigation infrastructure allows for better water management and reduce the risk of investing in a new technology (^{Minten and Barrett, 2008}). Also to achieve increased performance as well as improved seeds, necessary good management of soil fertility, use of appropriate fertilizers and correct dosage and control weeds, pests and diseases (^{Vanlauwe et al., 2010} and ^{Muzari et al., 2012}). The central hypothesis of this research is that the characteristics of the farmer and his production unit, as well as issues such as access to financial resources, infrastructure and markets related to the expected return and perceived risk are the factors that most influence in the decision-making improved seeds. As for innovation, it is expected that if the farmer already use or have taken certain innovations, also adopt improved seeds, although there is strong competition from those with native seeds, because their use is related to the adoption of a package technological.

Therefore, the aim of this study was to identify factors and innovations that influence the decision-making improved seeds of maize farmers in Oaxaca, in order to know their motivations and constraints, enabling the implementation programs arising from the implementation of public policy, are oriented is achieved efficiently and encourage the use of improved to reduce the deficit in the production of maize seed state.

Materials and methods

The identification of factors and innovations that influence the decision to adopt improved maize was conducted in 90 municipalities in the state of Oaxaca, in seven Districts of Rural Development located in seeds: Cañada, Coast, Huajuapan de Leon, Istmo, Sierra Juarez, Tuxtepec and Central Valleys. The data used for the study were obtained by mapping innovation networks in the state of Oaxaca 2013, conducted by the International Maize and Wheat Improvement Center (CIMMYT), and the Center for Technology Social Economic Research and Agribusiness and World Agriculture (CIESTAAM) of Autonomous University Chapingo.

The total population analyzed was from 2 118 maize producers who were selected by non-probability sampling, according to a multidisciplinary group of specialists researchers from both centers, based on their years of experience in the production of corn as working in the state. The selection criteria were achieving greater territorial coverage and cover the different profiles of Oaxacan farmers, which also have the willingness to be interviewed in their plots, for verification of the information requested. The enforcement of the surveys were technical advisors.

With the information obtained was built a database composed of quantitative and qualitative variables including among others, characteristics of the farmer and his production unit, practiced agricultural innovations, yields, access to resources in general and aspects of perceived risk. From it Logit models whose parameters were estimated with the maximum likelihood method (^{Agresti, 2007}), using the statistical package SAS 9.0 were built. These models are most often used to identify variables that influence the farmer's decision to adopt agricultural innovations (^{CIMMYT, 1993}).

The specification of the logit models is as follows (^{Gujarati and Porter, 2010}):

Where: L= the logarithm of the ratio of probabilities; ln= natural logarithm; Pi= prob (y = 1) conditional probability that a farmer use improved seeds; (1- Pi)= prob (y = 0); conditional probability that a farmer does not use improved seeds; βj's are the parameters to be estimated; Xij's= are the set of explanatory variables; y= εi is the error term.

For this study, two logit models were specified.

A first model to determine the factors that influence the likelihood of use decision improved maize seeds:

Use of seed=β₀ +β₁(EDA)+β₂(ESC)+β₃(SM)+β₄(ST) +β₅(REN)+β₆(CRE)+β₇(RIE)+β₈(VC)+ε_i

Where: "use seed" is the dichotomous dependent variable equal to one if the farmer uses improved maize seeds, and zero in contrary case in both models, the farmer using improved maize seeds, is one who he sowed certified seed category, acquired or received in commercial houses through the State Program certified seed Corn 2013. not using improved seeds, it is one who planted their own seeds nativas-. EDA is the age of the farmer; ESC is completed schooling farmer; SM is the maize area; ST is the total area available to the farmer; REN is the crop yield in 2013; CRED is access to credit; RIE is irrigation water regime and VC are contract sales.

A second model to determine the innovations that influence the probability of decision use of improved seed corn:

Using seed= β₀ +β₁(AS)+β₂(FB)+β₃(FF)+β₄(CM)+β₅ (CE)+β₆(CP)+ε_i

Where: "use seed" is the dichotomous dependent variable equal to one if the farmer uses improved maize seeds, and zero otherwise.AS= soil analysis; FB= balanced fertilizer (nitrogen, phosphorus and potassium and other limiting nutrients); FF= fractional fertilization (several applications at different stages of culture); CM= weed control (by chemical or physical methods); CE= disease control (via chemical methods); CP= and pest control (through chemical or biological methods).

Student t test was also performed to compare means of quantitative variables and determine the existence of signif icant differences between farmers using improved maize and those who do not use seeds. To analyze the association of qualitative variables with dichotomous dependent variable chi-square tests were performed.

Results and discussion

Out of a total of 2 118 producers, 25% used improved maize in the spring-summer 2013. On average seeds, these farmers are older and schooling than those who do not use improved seeds, twice hectares have both acreage corn as total area and yield per hectare. Also a higher percentage of them have access to financial resources, infrastructure and markets (Table 1).

Table 1. Relation of age, education, area planted to maize, the total area, yield, credit, irrigation and contract sales, with the use of improved seeds of maize in Oaxaca. 

Regarding innovations, the percentages are higher in farmers using improved seeds of maize, compared to farmers using native seed (Table 2).

Table 2. Relationship of soil analysis, fractional balanced fertilization, weed control, pests and diseases with the use of improved seeds of maize in Oaxaca. 

Comparing the two groups of farmers, it shows significant differences in both the factors studied and innovations, which means that are associated with a farmer's decision to adopt improved seeds. According to Logit models, factors contract sales, credit, yield, irrigation, education and the total area to be significant 1% influences the probability of decision making improved maize seeds (Table 3).

Table 3. Effect of age, education, area planted to maize, the total area, yield, credit, irrigation and contract sales in the decision to use of improved seed corn in Oaxaca. 

The innovations are affecting soil analysis, and fractional balanced fertilization and pest control, diseases and weeds (Table 4). The goodness of fit of the models had a correct prediction rate of 88%. However, according to the results of likelihood ratios are contract sales, credit, irrigation and performance, factors that have the greatest impact on the decision to adopt improved maize seeds. Innovations are soil analysis, and fractional balanced fertilization, in addition to control pests and diseases.

Table 4. Effect of soil analysis, and fractional balanced fertilization and weed control, diseases and pests, the decision to use of improved seed corn in Oaxaca. 

The contract sales were the most important factor influencing the decision to adopt improved maize seeds. Of farmers using improved seeds, 13% have sales contract; compared with only 0.1% of farmers who do not use them. Farmers with contract sales are 20 times more likely to use improved seeds than those who do not have a secure buyer for their production. On the other hand, the percentage of farmers using improved seed corn sales contract is low. Furthermore, when analyzing this variable associated with the average values both in total area sown to maize, shows that farmers using improved seeds cannot be considered commercial farmers, nor the extent size of the land they own and They sow nor by its orientation towards the market. In Oaxaca, most corn production is intended for self-consumption and marketed targets local markets.

According ^{Feleke and Zegeye (2006)} when farmers are far from markets tend to be less oriented the same, because their technology use decisions are based more on subsistence production in cost-benefit considerations.

Consequently, they are not interested in investing their scarce resources on improved seeds, as long as native seeds provide them with solvent production needs. In that sense, the opportunity cost of changing the native seeds improved seeds, means for subsistence farmers, not having to buy corn, because with the performance increase could meet their household demand and for farmers who decide to produce for the market of investing and adopt the technology package holistically them to generate higher production.

According to ^{Mabah and Oyekale (2012)}, if a farmer changes from subsistence to a oriented market production, the probability of adopting the complete technology package for corn approaches 1; i.e. the probability thatadopt it completely. ^{Alene (2007)} in his study on maize production in Ethiopia, found that farmers increased their production on average 26% if adopted best practices, along with optimal use of inputs. This allowed reducing production costs by an average of 39%, which increased the profitability of improved maize production.

With respect to yields, farmers using improved maize seeds have 3.5 t ha^-1 average yield, which exceeds both the average national production (2.91 t ha^-1) and the state (1.22 t ha^-1), while those who do not use them have an average of 1 t ha^-1. In addition, to an increase in the average yield, the probability of use of improved seed increases 3.6 times. Irrigation also highly significantly influence the decision to use improved maize seeds. Of farmers using improved seeds, 34.9% are under irrigation compared with 7.4% of those who use it. The farmers with irrigation, are 3.6 times more likely to use improved seeds than those who have temporary.

Access to credit proved to be the second most important factor in the decision to use improved seeds. Of farmers using improved seeds, 17.6% have access to credit, compared with less than 1% of those who use them. Farmers with access to credit, are 5.7 times more likely to use improved seeds, that those who do not. However, 82.4% of farmers using improved seeds in the state have no access to credit.

In addition to the imperfections in the credit markets, problems of accessibility due to the inability of a borrower to commit to compliance with a debt contract. To counter that aspect, ^{Giné and Yang (2009)}, mention that strategies have been implemented as in the case of Malawi, where microfinance institutions provide loans for hybrid seed to groups of 10 to 20 farmers as collective agreements liability. That way, each farmer have their individual loan, but the group is jointly liable for all loans.

Similarly, ^{Muñoz et al. (2002)} mention the experience in Mexico of the Service Centre for Rural Development of Puebla A. C., whose strategy of financial intermediation was the formation of solidarity at the level of ejidos or communities groups. Groups by encouraging savings, may be eligible for a loan, but all have joint responsibility for the loans received by each of its members, so that if any member fails to pay its credit, suspended the credit to the whole group to exert pressure on the defaulter. With regard to innovations, soil analysis, it was the most impact on the decision-making improved seeds. Farmers who use them, 18.8% do soil tests compared with 2.3% of farmers who do not use them. Farmers who make soil analysis, are 5.8 times more likely to use improved seeds, that those who do not perform.

In addition, both balanced fertilization as fractional turned out to be innovations that also influence. Of farmers using improved seeds 45.6% make balanced fertilization and fertilization fractional 40.9% compared with 17.3% and 18.6% respectively of farmers planting native seeds. Furthermore, farmers make balanced fertilization are twice as likely to use improved seed as those who do not fertilize that way. As for the control of pests and diseases, farmers using improved seeds, 37.3% make disease control and pest control 61.2% compared to 11.8% and 25.6% respectively of farmers planting seeds of local varieties.

The above results show that in the case of Oaxaca itself is undergoing a process of full adoption, because farmers using improved seeds, also perform the recommended innovations of technology package for corn. ^{Alene and Hassan (2005)} found that although farmers used improved seeds, most were partial adopters who did not adopt the crop management practices recommended to fully exploit the potential of improved corn yield. The adoption of the entire technology package is important because it is more profitable than the adoption of a component or components of the package.

Conclusions

The contract sales, access to financing and availability of irrigation are the main factors that determine the adoption of improved maize by farmers in the state of Oaxaca seeds. Being in this study, contract sales, the most important is associated with the adoption of technology in the production units.

The main technological innovations that determine the adoption of improved maize in the state of Oaxaca seeds are soil analysis, balanced, fractional fertilization and control of pests and diseases.

The factors and technological innovations associated with the adoption of improved maize in the state of Oaxaca seeds are holistically technological aspects that favor the acquisition of technology in the production units. Both condition the adoption of improved maize seeds as a means to improve production. The promotion of public programs aimed at boosting productivity by using improved maize in the state of Oaxaca seed, should consider both factors as innovations associated with the adoption of improved seed production units.