4.1. Farmers’ Assessments on Promising Rice Lines
The participatory approach which highlighted farmers’ preference data was quantified as feedback to enhance the research in rice breeding. This opened up opportunities for farmers’ choice. The cooperation between breeders and farmers becomes an active partnership in plant breeding [
47].
The opened up opportunities consisted in well-adapted rice varieties, high productivity, and farmer’s choice. Participatory methods are needed to widen the impact of a range of technology innovations in agriculture and plant breeding management. The growing scarcity of resources for research increased the demands to provide evidence that participatory methods are justified by the results. Participatory research and farmers’ preferences of new rice lines aim to know and understand the characteristics of rice that are important for farmer adoption.
The respondents of this study came from diverse gender, age, education, and farming experience. In fact, they also possess different areas of land. This is the ideal expected proportion to describe information about the needs of certain rice varieties. It is necessary to present diverse respondents to investigate consumer preferences, including distinctness in socio-economic characteristics at the same time, and places where actual decisions were made to better elicit their true preferences [
48]. Farmers’ preferences did not vary too much in terms rice productivity, disease resistance, and pest resistance.
The gender imbalance can limit the potential of this sector. The age of the actors involved in the rice production process also affects productivity. The younger farmer has the ability to work harder, invest in new technologies, include new varieties, and improve rice production. Levels of education can increase the potential advantages of new technologies and interventions to ensure the effective promotion of rice varieties. Furthermore, differences in age, education, and farm size, also influenced the adoption and farmers’ acceptability of new rice varieties [
49,
50,
51].
The total preference level and phenotypic performance data showed Gamapadi-2 and Gamapadi-4 were the most preferred for breeding and were to be released as commercial varieties. Farmer’s preference variations in the promising rice lines are revealed in all locations. The diversity of preferences reflected in the three locations is an important capital in the efforts to increase genetic diversity in the field. It is hoped that farmers can continue to grow their preferred lines or varieties according to their individual tastes and to share their seeds with other farmers. The attribute rice data represented that rice productivity was the most important characteristic according to farmers. This result suggests that rice breeders develop new lines that meet farmers’ needs.
Participation also has an important role in increasing the genetic diversity of rice in the field. Additionally, the participation of farmers with the information channel for the diffusion of seeds of superior varieties of rice in other farmers’ land is beneficial [
52,
53,
54]. Research by Lacoste et al. (2012) [
17] showed that the diffusion strategy of superior varieties through a participatory approach was able to significantly increase the number of farmers adopting different varieties.
The control strategy for brown planthopper and
Xoo disease is by the breeding plants’ genetic resistance and developing environmentally-friendly rice cultivation [
55,
56,
57]. The sources of resistance
Pyricularia oryzae which were identified from genetic resources can be explored in future multiple resistance rice breeding programs [
58,
59]. The rice cultivars that had resistance to
Xoo will be useful as genetic sources in breeding programs to overcome existing bacterial blight disease.
The use of the Importance Performance Analysis (IPA) method served to find out which attributes are still underperforming or which must be maintained. From here, proposals can be determined to improve important attributes, but performance is still too poor to improve service quality according to what is expected and will have an impact on farmer satisfaction with rice lines. According to the farmers’ preferences, Gamapadi-2 and Gamapadi-4 are expected to be released as commercial lines and adopted by farmers because they have liked it even before it became a variety. Compared to the two, the other lines get various values from 120 respondents who participated in the observation.
4.2. The Yield of Promising Rice Lines
The magnitude of the role of genetic and environmental factors in determining the level of phenotypes can be estimated from variance analysis with a certain design. The interactions between genotype and environment are very important in rice breeding. This interaction provides different diversity between genotypes at certain locations. The lines that have good diversity in one location do not necessarily display good performance in another location tested.
Evaluation of promising rice lines on various environmental conditions was performed with statistical GGE biplot. This is a combined analysis model that showed the effects of the genotype plus the interaction between genotype and environment [
60]. The analysis was conducted to observe stable rice lines at three locations. GGE biplot graphic demonstrated visual information referring to the evaluation on rice lines, location, and their interactions.
The GGE biplot method can indicate adaptability and the suitability of rice lines. The straight line from the biplot points vertically across the connection on each side and divides the biplot line into sectors in which each sector has a line vertex. It results in five sectors. Two sectors contain the environment and the rest sectors do not contain the environment [
61]. Research showed Gamapadi-2 is the most stable of the lines and has the highest mean yield in various locations and is categorized as the recommended genotype for wide-scale planting. Gamapadi-2 possesses the closest distance from the biplot point. The GGE biplot can classify the line into four categories and show yield performance and adaptability in each area. The vertex genotype is the best in the environment that is in the same vector and so each vertex is the genotype that has the best local adaptation in each mega-environment. The stability of the rice lines in all environments presented high grain yield. The interaction between genotype and environment causes the rice to indicate crop ability on each different location [
62].
The Average Environment Coordination (AEC) ordinate method can indicate the stability of rice lines [
63]. The image with one arrow passing the midpoint of the environment (the origin of the biplot) is the AEC abscissa depicting the mean line results for all environments. The small circle in the AEC line represents the environmental mean. The direction of the AEC abscissa arrow is drawn past the origin of the biplot and the circle of environmental means. Meanwhile, the perpendicular line from the abscissa of the AEC is the ordinate of the AEC. Absis AEC following the direction of the arrow indicates the greater effect of the genotype. Gamapadi-2 showed the most stable lines, has the highest mean yield in various locations, and is categorized as the recommended genotype for wide-scale planting. The GGE biplot focused scaling showed the ideal lines were Gamapadi-2, BP 20314d-SKI-16-1-2, and BP 30475b-SKI-6-4-3. The genotypes have a high average yield and stability [
8].
4.3. Pest and Disease Resistance of Promising Rice Lines
The requirement for superior rice lines includes biotic (pests and diseases) resistance. Pest and disease are disrupting crops, obstacles, and reducing potential production. Brown planthopper is one of the major rice pests. They directly destroy crops by sucking up plant fluids that cause dry plants and hopper burn.
Nirlava lugens indirectly becomes a vector of spreading rice ragged stunt virus and grassy stunt virus. The enhanced insect-resistant rice line is a key component of the required response to increased rice quality [
64]. The explosion of brown planthopper happened in several rice-growing areas in Asia. Excessive use of insecticides is also a factor in the occurrence of brown planthopper explosions and the population is continuously increasing [
65,
66].
The distribution of major pests and diseases at the three study sites (Banyumas, Klaten, and Batang) for the last decade has also fluctuated.
Nilaparvata lugens in 2017–2018 has caused and influenced lower productivity on 8385 ha of productive rice fields at Banyumas (7291 ha), Klaten (823 ha), and Batang (271 ha). In fact, Banyumas (July 2017) paralysis occurred in more than 2768 ha of rice fields, although in 2018 this pest attack was controlled to below 170 ha (September 2018 in Banyumas) [
5,
6]. Research in Central Java shows that the response of all lines to brown planthopper in the field were almost the same value in all phases of plant growth (score 0). It can be hopeful for the development of resistant rice lines.
Bacterial blight is the most destructive disease of rice. The bacterium
Xanthomonas oryzae PV.
oryzae causes yellowing, drying of leaves, and wilting at the seedling stage. Furthermore, blight lesions give a striped appearance on the leaves and field patches infested with whitish and ragged appearance [
58]. In terms of the major constraints in rice, incidences related to this disease, in 2017 and 2018, reached 3131 ha in Banyumas, Klaten, and Batang. The peak of this disease in three locations generally occurs from January to April every year. The most damaged areas were located in Klaten (1293 ha). Over the past two years (2017–2018), Banyumas and Batang have also been affected by this disease (1187 and 651 ha, respectively) [
5,
6].
The fungus
Pyricularia oryzae can cause leaf blast disease and serious damage to rice leaves. Blast has been identified from different regions of the country. This pathogen can decrease the potential yield of rice and is active during wet season (January–April). This fungus leaf blast attacks more than 827 ha within two years (2017–2018) in Banyumas (150 ha), Klaten (527 ha), and Batang (150 ha). [
5,
6]. The symptoms of
Pyricularia oryzae in susceptible rice lines are marked with gray spots surrounded by dark green to dark brown colors and tapered borders. In humid conditions, the lesions develop rapidly to cover the entire surface of the leaf.
Field research was conducted during the rainy season, data in three locations showed temperatures ranging 22.83–31.39 °C, relative humidity conditions were almost similar at around 80%, fastest wind speed (>9.61 km/h) and high rainfalls (1856–6158 mm) (
Table 3). This affected the reaction of rice lines to leaf blasts. Gamapadi-9 in Klaten and Gamapadi-9 and Gamapadi-10 in Batang performed a surface area of infected leaves ranged >10–<50%. The climatic situation is causing the symptoms of bacterial leaf blight in Klaten, with area of symptoms on leaf surfaces >50–<75% (BP 20314d-SKI-16-1-2 and Inpari 30 Ciherang Sub 1). The impact on plants affected by this disease showed that rice productivity of promising rice lines is not profitable. Gamapadi-9 (3.75 t/ha) possess the lowest productivity in Batang and a poor average yield (4.86 t/ha) in all locations.
In contrast, Gamapadi-2 possess the highest yield (10.60 t/ha). Gamapadi-2 at Banyumas (8.91 t/ha) and Klaten (7.74 t/ha) also showed the best average productivity compared to other lines, while Gamapadi-4 in Batang has the highest yield (6.72 t/ha) with an average of 6.98 t/ha from all study locations. Gamapadi-2 and Gamapadi-4 both have the potential for resistance to brown planthopper and both showed no symptoms of damage and no populations were found. The reaction of promising rice lines Gamapadi-2 and Gamapadi-4 to leaf blast also indicates that the majority possess no infections. Both lines showed the potential for no symptoms of bacterial leaf blight during the initial phase of growth. This Xoo constraint affects all lines at the age of 78 and harvests, but Gamapadi-2 and Gamapadi-4 only indicated areas of symptoms on leaf surfaces >1–<5%.
The characteristics of rice resistance are important because they determine the willingness of farmers to plant the new varieties. The most critical criteria in predicting acceptable lines were based on visual observation. Preferences are created from a set of characteristics that are known and relatively valued by consumers [
67].
Participation can be efficacious for the evaluation of the nature of rice lines, for the identification of acceptable lines, and the supplementation of breeders’ observations. Rice breeding needs to set goals regarding variety characteristics and farmers’ criteria. It is an opportunity of the visiting program to view demonstration plots and to understand farmers’ preferences for different varietal characteristics.