The increasing world population and the increase in the food demand states important challenges for the agricultural sector, where the production had to increase in a 60% for 2050; using lands which has been cultivated, all in order to produce more, using less natural resources and at the same time to face a changeable climate (Parra-Cortés et al. 2019Parra-Cortés, R.I., Magaña-Magaña, M.A., Piñeiro-Vázquez, A.T. 2019. "Intensificación sostenible de la ganadería bovina tropical basada en recursos locales: alternativa de mitigación ambiental para América Latina". ITEA-Información Técnica Económica Agraria, XX: 1-18, ISSN: 2386-3765. https://doi.org/10.12706/itea. ). That is why the sustainability of the livestock systems is worrying every time, facing the need to create eco-efficient environments for the adaptation to the climate change.
The developing of new biological technologies that provides effective answers against the climate change, had leads the generation of technological package to face these challenges, among these packages is the improvement of forage species. The naturalized grasses are characterized for its low to medium productivity and low protein contents (Ruíz and Guevara 2021Ruíz, R.I. & Guevara, R.V. 2021. "Reseña sobre aspectos nutricionales para el desarrollo sostenible de sistemas ganaderos basados en pastos y forrajes tropicales". Revista Ecuatoriana de Ciencia Animal, 5(2), ISSN: 2602-8220. ). During the dry seasons the dry matter availability of these grasses drastically decrease, giving as result soil erosion (cover loss), decrease in weight gain and milk production (Lamela et al. 2022Lamela-López, L., Amechazurra-Rodríguez, L.R., Montejo-Sierra, I. L., García-Fernández, D. & Lay-Ramos, M.T. 2022. "Producción de carne bovina a partir de pastos naturales y suplementación con concentrados de harinas de plantas proteicas". Pastos y Forrajes, 44: eE35, ISSN: 2078-8452. and Navas 2022Navas, A. 2022. "Percepciones de pequeños productores sobre cambios en el clima y su efecto en sistemas de producción de leche". Revista de Investigaciones Veterinarias de Perú, 33(2): e20543, ISSN: 1682-3419. https://doi.org/10.15381/rivep.v33i2.20543.).
The perspectives of the world population increase in medium term are important; giving place to the need of intensifying the agricultural production, through the use of new cultivars that produce more, with less amount of resources, which is only possible by means of genetic improvements techniques (De los Reyes 2019De los Reyes, B.G. 2019. "Genomic and epigenomic bases of transgressive segregation - New breeding paradigm for novel plant phenotypes". Plant Science, 288: e110213, ISSN: 1873-2259. https://doi.org/10.1016/j.plantsci.2019.110213. ).
The Instituto de Ciencia Animal (ICA) developed an improvement program of Cenchrus purpureus, through the use of biotechnology. Using techniques of tissue culture and regeneration of in vitro plantlets emerged new different clones from the progenitor (Herrera and Martínez 2006Herrera, R.S. & Martínez, R.O. 2006. Mejoramiento genético por vías no clásicas. En: Pennisetum purpureum para la ganadería tropical. Eds. Herrera, R.S., Febles, G. y Crespo, G. Instituto de Ciencia Animal. La Habana, Cuba. p.15.), which allowed to increase the diversity of the available germplasm. One of the objectives achieved with the application of biotechnology was the obtaining of new clones with better agronomic characteristics and high quality for their use as forage or in grazing.
The objective of this study was to evaluate the performance of morphologic indicators and the relations of height and yield with the age, of C. purpureus new clones obtained in Instituto de Ciencia Animal for their use in grazing.
Materials and Methods
⌅Location, climate and soil
⌅The experiment was carried out in Centro Experimental Miguel Sistachs Naya from ICA, located between the 22º 53 NL and 82º 02 WL, at 80 m o.s.l (Anon 1989Anon. 1989. Atlas Nacional de Cuba. (Ed). Instituto de Geografía de la Academia de Ciencias de Cuba e Instituto Cubano de Geodesia y Cartografía. Impreso por el Instituto Geográfico Nacional de España.); in a typical red ferrallitic soil (Hernández et al. 2015Hernández, J.A., Pérez, J.J.M., Bosch, I.D. & Castro, S.N. 2015. Clasificación de los suelos de Cuba. Ed. Ediciones INCA, Mayabeque, Cuba. ISBN 978-959-7023-77-7. 93p.).
Some climatic data of the experimental period are showed in figure 1, which were taken from the Estación Meteorológica del Instituto de Ciencia Animal. During the first year the highest accumulation of rainfalls was in June and July, while in the second year was in June and September. The maximum temperature had high values in August and September for the first year and in July and August in the second year. The minimum temperature had low values in January and March of the first and second year, respectively.
Treatments and design
⌅The treatments consisted on five clones of C.purpureus with promising characteristics for grazing: CT-3, CT-7, CT-11, CT-26, CT-27 and were compared with its progenitor C. purpureus cv. Cuba CT-115. A random block design was used, with four replications which were 25 m2plots, constituting the experimental unit.
Experimental procedure
⌅A conventional preparation of the soil was carried out and seeds of five month of age were planted in 5 x 5 m plots, with sowing distance between rows of 0.90 m. The plot was cut at 10cm over the soil level, always with border effect.
The samples were performed every 90 days of regrowth during the dry season and every 60 days during the rainy season, under dry conditions and without fertilization, the experiment was carried out during the years 2016 and 2017. All the cut material was homogenized, weighed and a random sample of 500 g per plot was taken. The sample was manually separated in leaves and stems which were introduce in a circulation air oven at 60 ºC until constant weigh. The following morphological indicators were determined: length and wide of the four leaves completely expanded, number of leaves (No. Leaves), plant height and dry matter yield (DM) according to Herrera (2006)Herrera, R.S. 2006. Fisiología, calidad y muestreos. En: Fisiología, producción de biomasa y sistemas silvopastoriles en pastos tropicales. Abono orgánico y biogás. R.S. Herrera, I. Rodríguez y G. Febles (Eds.). EDICA. Instituto de Ciencia Animal. La Habana, Cuba. methodology. For the original variable No. of leaves the theoretical assumptions of the Analysis of Variance normality of residues were analyzed by the Shapiro-Wilk (1965)Shapiro, S. & Wilk, B. 1965. "Analysis of variance test for normality (complete samples)". Biometrika, 52 (3/4): 591-611, ISSN: 1464-3510. https://doi.org/10.2307/2333709. test and homogeneity of variance by Levene (1960)Levene, H. 1960. Robust tests for the equality of variance. Contributions to Probability and Statistics. Stanford University Press. pp. 278-292., both were unfulfilled, so the variable was transformed according √X, and improve the fulfillment of those assumptions, so the analysis was performed according to the proposed design.
To establish the relation between the plant height and yield (dependent variables) with respect to the regrowth age (independent variable), lineal, quadratic and cubic models were used. To select the model of better goodness of fit the statistical criteria determination coefficient (R2), signification of the model and standard error of the indicators estimation proposed by Guerra et al. (2003)Guerra, C. W., Cabrera, A. & Fernández, L. 2003. "Criteria for the selection of statistical models in scientific research". Cuban Journal of Agricultural Science, 37(1): 3-10, ISSN: 2079-3480. and Rodríguez et al. (2013)Rodríguez, L., Larduet, R., Ramos, N. & Martínez, R.O. 2013. "Modelling of dry matter yield of Pennisetum purpureum cv. king grass with different cutting frequencies and N fertilizer dosages". Cuban Journal of Agricultural Science, 47(3): 227-232, ISSN: 2079-3480. were taken into account.
Statistical analysis
⌅Analysis of variance was used, according to the proposed design and for means comparison the Duncan (1955)Duncan, D. B. 1955. "Multiple ranges and multiple F. test". Biometrics. 11:1-42, ISSN: 1541-0420. https://doi.org/10.2307/3001478. test was used, for p<0.05. The information was processed in the statistical program IBM (2012)IBM SPSS Statistics Versión 22. 2022. Software estadístico de tecnología asistencial McGrawHill/Interamericana de España, S.A.V. p. 358..
Results and Discussion
⌅The performance of some morphological indicators of the clones evaluated in the rainy season is show in table 1. In the two studied years there were significant differences between the evaluated clones for the studied indicators. The length and wide of leaves showed a variable performance in this climatic period. In the case of leaves length the performance of all clones was similar to their progenitor, except in CT-7 with value of 83.20 cm. However, in the second year the clones CT-3, CT-7 and CT-11showed the highest leaves length. With respect to the leaves wide all the clones had similar characteristics to the progenitor in the first year, except CT-3 which had the highest value with 2.50 cm, while in the second year the superiority in this indicator were showed by the clones CT-3, CT-11, CT-26 and CT-27.
Clones | First year | Second year | ||||
---|---|---|---|---|---|---|
Leaf lenght (cm) | Leaf wide (cm) | No. of leaves/plant | Leaf lenght (cm) | Leaf wide (cm) | No.of leaves/plant | |
CT-3 | 86.85ab | 2.50a | 2.82a (7.95) | 81.45a | 2.88a | 3.51ab (12.32) |
CT-7 | 83.20b | 2.03b | 2.59bc (6.71) | 78.50ab | 1.95b | 3.62a (13.10) |
CT-11 | 87.75a | 2.20b | 2.56 c (6.55) | 82.50a | 2.45ab | 3.59a (12.89) |
CT-26 | 86.75ab | 2.13b | 2.60 bc (6.76) | 71.05 c | 2.18ab | 3.3bc (11.15) |
CT-27 | 90.13a | 2.18b | 2.68b (7.18) | 76.23abc | 2.25ab | 3.45ab (11.90) |
CT-115 | 90.13a | 2.15b | 2.59 bc (6.71) | 74.30bc | 1.85b | 3.14 a (9.86) |
SE± | 1.35 | 0.06 | 0.03 | 1.98 | 0.23 | 0.07 |
p | 0.0234 | 0.0013 | 0.0002 | 0.0077 | 0.0340 | 0.0013 |
abc Values with non common letters per column differ at P<0.05 (Duncan 1955Duncan, D. B. 1955. "Multiple ranges and multiple F. test". Biometrics. 11:1-42, ISSN: 1541-0420. https://doi.org/10.2307/3001478.)
Original data between parenthesis ( )
The number of leaves per plant was higher in the clone CT-3 in the first year, while in the second year all the clones showed superiority in this indicator with respect to the progenitor, except CT-26 which was similar to the control (table 1).
In the dry season, the length and wide of leaf in the first year was higher in CT-115 in comparison to the rest of the evaluated clones (table 2). During the second year, the clones CT-7 and CT-11 had leaves length similar to the progenitor, while the rest had lower values of this indicator.
Clones | First year | Second year | ||||
---|---|---|---|---|---|---|
Leaf lenght, cm | Leaf wide, cm | Number of leaves /plant | Leaf lenght, cm | Leaf wide, cm | Number of leaves/plant | |
CT-3 | 65.93e | 1.82c | 4.12a (17) | 31.98c | 0.85d | 3.28ab (10.76) |
CT-7 | 75.38c | 2.25b | 2.51 (6.3) d | 49.43ab | 1.25b | 2.52c (6.35) |
CT-11 | 87.90b | 2.25b | 2.61 (6.8) d | 60.03a | 1.55a | 2.34 c (5.47) |
CT-26 | 65.98e | 1.72c | 3.84 (14.7)b | 37.65bc | 0.95cd | 3.10 b (9.61) |
CT-27 | 70.01d | 1.69c | 3.55 (12.6)c | 37.00bc | 0.88cd | 3.37 a (11.36) |
CT-115 | 91.50a | 2.44a | 2.55 (6.5)d | 51.78a | 1.03c | 2.32 (5.38) |
SE± | 1.18 | 0.06 | 0.05 | 3.96 | 0.05 | 0.08 |
p | 0.0001 | 0.0001 | 0.0001 | 0.0011 | 0.0001 | 0.0001 |
abcdeValues with non common letters per row differ to P<0.05 (Duncan 1955Duncan, D. B. 1955. "Multiple ranges and multiple F. test". Biometrics. 11:1-42, ISSN: 1541-0420. https://doi.org/10.2307/3001478.)
Original data between parenthesis ( )
The leaf wide was higher in CT-11in comparison to the rest of clones with value of 1.55 cm. It is important to highlight that although it was not compare between years there was a marked reduction of the values length and wide of leaves from the first to the second year, which could due to the loss of young vigor and to the adverse conditions of the climate during the dry season of the second year where rainfalls were very limited.
In the first year the clones CT-3 and CT-26 showed higher number of leaves/plant in this climatic period, while in the second year besides of these clones, CT-27 was highlighted. This characteristic has high value for the selection of varieties for forage or in grazing since, besides the leaves constitutes the fraction more intakes by the animals, is also determining in the biomass production. The leaves content is an element of vital importance for the synthesis of the necessary compounds for the growing and developing of the plant, if is considered that is in this fraction of the plant where the photosynthesis take place (Prochetto 2021Prochetto, S. 2021. Evolución de la Fotosíntesis: dinámica del desarrollo foliar de gramíneas. Tesis en opción al Grado Científico de Doctor en Ciencias Biológicas. Universidad Nacional del Litoral, Facultad de Bioquímica y Ciencias Biológicas. Argentina. 188p.).
The variability found in this study, could due to the changes produced in the growing and developing of the plant, as result of the interaction of the genetic potentialities and the environmental factors, which in known as genotype-environment interaction. Studies developed by Reyes-Pérez et al. (2021)Reyes-Pérez, J.J., Méndez- Martínez, Y., Luna-Murillo, R.A., Espinosa-Coronel, A.L., Triviño-Bravo, J.L., Guzmán-Acurio, J.A & Ledea-Rodríguez, J. L. 2021. "Evaluation of fertilization in agronomic morpho responses of Cenchrus purpureus varieties at different ages of regrowth". Tropical and Subtropical Agroecosystems, 24: 08, ISSN: 1870-0462. show a great variability between varieties of Cenchrus purpureus at different regrowth ages evaluated under the same conditions of climate and soil and in response at different fertilization variants.
In table 3 are show equations that relate the height and yield with the regrowth age in the rainy season. All the clones showed quadratic relations between height and age, with high determination coefficients, while for the yield lineal, quadratic and cubic models with determination coefficients high too were fitted, although in some cases as it was for CT-7 this coefficient was lower than for the rest of the relations founded.
Clone | Equation, Y: Height, cm X: Age, days | R2 |
---|---|---|
CT-26 | Y= -79.09 + 4.318 (± 0.90) X-0.021(± 0.007) X2 | 0.97** |
CT-115 | Y= -73.55 + 4.267 (± 0.34) X-0022 (± 0.002) X2 | 0.99*** |
CT-27 | Y = -58.317 + 3.773 (± 0.60) X-0.022 (± 0.004) X2 | 0.96** |
CT-3 | Y = -66.091 + 3.986 (± 0.47) X -0.021 (± 0.003) X2 | 0.99*** |
CT-7 | Y= 47.354 + 3.062 (± 0.39) X +0.018 (± 0.003) X2 | 0.98** |
Clone | Equation, Y: Yield, t/ha X: Age, days | R2 |
CT-26 | Y= 0.013 + 0.004 (± 0.001) X | 0.88** |
CT-115 | Y= 0.477-0.024 (± 0.006) X+ 0.0001(± 0.0001) X2-0.0000247 (0.0001) X3 | 0.99* |
CT-27 | Y = 0.167 + 0.001 (± 0.0001) X | 0.86** |
CT-3 | Y= -0.153 + 0.010 (± 0.002) X-0.0000544 (± 0.0001) X2 | 0.96** |
CT-7 | Y= 0.147 + 0.001 (± 00001) X | 0.73* |
*P<0.05 **P<0.01 ***P<0.001
In table 4 are show the relations founded for the dry season. In this case all the clones showed quadratic relations between height and age, except the CT-7 which had a lineal relation, the determination coefficient and signification were high. For the yield, cubic models for all the clones were fitted, except for CT-115 and CT-7 that were lineal, the determination coefficients and signification were high too.
Clones | Equation, Y: Height, cm X: Age, days | R2 |
---|---|---|
CT-26 | Y= -45.271 + 4.42 (± 0.45) X - 0.029 (± 0.004) X2 | 0.98*** |
CT-115 | Y= 27.20-1.090 (± 0.896) X + 0.021(± 0.007) X2 | 0.94** |
CT-27 | Y= -38.61 + 3.85 (± 0.46) X-0.022 (± 0.004) X2 | 0.98*** |
CT-3 | Y= -50.986+4.788 (± 0.392) X-0.29 (± 0.003) X2 | 0.99*** |
CT-7 | Y= 42.743+1.713 (± 0.334) X | 0.84** |
Clones | Equation, Y: Yield, t/ha X: Age, days | R2 |
CT-26 | Y = 48.140-3.902 (±1.46) X + 0.105 (±0.027) X2-0.001 (± (0.0001) X3 | 0.99** |
CT-115 | Y= -27.689 + 1.363 (± 0.188) X | 0.91*** |
CT-27 | Y= 28.32-2.425 (± 1.10) X + 0.75 (± 0.021) X2 + 0.0001(± 0.0001) X3 | 0.99** |
CT-3 | Y= 48.389 - 4.344 (± 1.87) X + 0.136 (± 0.035) X2-0.001(± (0.0001) X3 | 0.99** |
CT-7 | Y= -5.79 + 0.597 (± 0.107) X | 0.86** |
*P<0.05 **P<0.01 ***P<0.001
Vieira da Cunha (2006)Vieira da Cunha, M. 2006. Caracteristicas estruturais e morfológicas relacionadas à eficiênçia de pastejo em Pennisetum sp. no período de seca. Master thesis. Universidade Federal Rural de Pernambuco, Brasil. when evaluating varieties of Cenchrus stated that the height and density of the leaf sheath were fundamental indicators to describe and explain the variability between plants, while Romalo Faca (2008)Romalo Faca, A. 2008. Avalaçao de clones de capim-elefante (PennisetumpurpureumChum) para la utilização encapineira no cerrado matogrossense. Master Thesis. Univ. Federal de Mato Grosso, Brasil. when studying 14 clones of this genus report the importance of the height and length of leaves, among other indicators, for establishing the differences among them.
Castañeda et al. (2015)Castañeda, L., Olivera, Y. & Wencomo, H. 2015. "Selección de accesiones de Pennisetum purpureum para fomentar sistemas de alimentación ganadera". Pastos y Forrajes, 38 (2): 170-175, ISSN: 2078-8452., Ray et al. (2016)Ray, J., Herrera, R.S., Benítez, D., Díaz, D. & Arias, R. 2016. "Multivariate analysis of the agronomic performance and forage quality of new clones of Pennisetum purpureum drought tolerant in Valle del Cauto, Cuba". Cuban Journal of Agricultural Science, 50(4): 639-648, ISSN: 2079-3480. and Olivera et al. (2017)Olivera, Y., Castañeda, L. & Toral, O. 2017. "Caracterización morfobotánica de plantas de Cenchrus purpureus (Schumach) Morrone provenientes de una colecta nacional". Pastos y Forrajes, 40(3): 184-187, ISSN: 2078-8452. when evaluating different varieties of Cenchrus found that the amount of leaves, length and wide of leaf and the height were highlighted indicators to explain the variability among plants.
It is concluded that the most highlighted clones in the evaluated indicators, mainly in the dry season, which is the most critical for the production of animal food, were CT-3, CT-26 and CT-27. It is recommended to evaluate these highlighted clones under grazing conditions and deep on the performance of its nutritive value.