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1 DIVERSIFICATION OF SUGARCANE VARIETIES FOR CATTLE FEED AND SUSTAINABILITY By H. JORGE, O. SUÁREZ, H. GARCÍA, I. JORGE and L. BENITEZ Instituto Nacional de Investigaciones de la Caña de Azúcar, Habana. Cuba KEYWORDS: Cattle Feed, Digestibility, Dry Matter, Soils, Abiotic Stress. Abstract THE PAPER reports results of a study of 44 sugarcane genotypes, evaluated as cattle feed, at 13 months of age, in the first ratoon crop, at Villa Clara Cienfuegos Territorial Sugar Cane Research Station and the Sancti Spir itus National Breeding Center in Cuba. Fourteen tr aits we re evalua ted by m eans of m ultivariate an alyses (Prin cipal Components and Discriminant Function), and also a sim ulation was conducted of agroecological regionalisation for the allocation of the sugarcan e varieties according to the main limiting factors (drought and poor dr ainage) on a cattle producing farm. Results showed that the variables, percentage of stalk fresh weight (% of stalks) and of tops (% of tops), had high influence in the first principal component, whereas the genetic disease (smut and rust) resistance had high influenc e in the second com ponent. It should be pointed out that the percenta ge of digestibility of the dry m atter sh owed very little variability, which indicates a high stability of this tra it. The Discrim inant Functio n Analysis a llowed class ification of cultivars into thre e gro ups: var ieties of low f orage value (below 40% digestibility of the dry m atter), varieties of intermediate forage value (between 40 50%) and varieties of high forage value (a bove 50% digestibility). Results allowed the recomm endation of 21 new genotype s, characterised by th eir resistance to main diseases and their high forage value, and nine were superior to the control My5514, four suitable for waterlogging st ress and three for drought stress. The simulation of the agro-ecological regionalisation enabled spatial location and modelling for the appropriate establishm ent of individua ls, in agre ement to the ir d igestibility, tolerance to the two environmental stresses (waterlogging and drought) and their disease resistance. Introduction Population growth is a problem in the worl d, today. It is probable that population will increase to in 2025 (FAO, 1998). This must be viewed in the contex t of a decrease in the ar ea of arable land committed to food production becau se of com petition for applic ation of pasture and gr ain crops to energy production. Mankind has knowledge and technol ogies to confront this cr isis, but polic ies of unequal distribution of wealth have resulted in som e negativ e environm ental and social impacts (FAO, 1996). Sugarcane constitutes an alte rnative to be u sed for anim al nutritio n. Countries lik e Colombia, Brazil and Costa Rica maintain that the tec hnical an d biological basis exists for sugarcane to replace cereals in in tensive animal production system s, thus allowing the release of great quantities of foodstuff for mankind. 1

2 This paper was developed to characterise a group of varieties of sugarcane for use as anim al food and for identifying suitable agro-ecological en vironments for them to be used as cattle producing units. Materials and methods The study was developed in two provinces of the country (Villa Clara and Sancti Spíritus) at the Suga r Com panies Ifraín Alfo nso and Melanio Hernández, in soil Eutric Cambisol (FAO UNESCO, 1994). Forty-four recently reco mmended new varieties of sugarcan e from the Sugarcane Research National Institute for Sugar Production were studied. The plots w ere of 64 m 2, with five replications in the first ratoon crop harvested at 13 months of age. Fourteen variab les relating to crop m orphology and the probable relationship with the digestibility of the biomass were evaluated. Genetic resistance against two important diseases, brown rust and sugarcane sm ut, was also quantified. The digestibility of the d ry matter of each variety was determ ined by the in vitro technique of KOH (Kesting, 1977). The statis tical an alysis was perfo rmed usi ng the m ultivariate analyses of Principal Components and Discriminant Functions, in which the digestibility of the dry m atter was used like a group variable, with three groups: <40 %, >50 % and the correspondent interval. The varietal perform ance was ass essed by com paring means of the percentage digestibility of dry matter with the control variety My5514. The software MapInfo 8.0 was used for the agro-ecological zoning simulation on a cadastral base map of 1:10000 scale. The utilisation of 90% of the area of the unit was assumed for cattle raising, and the distribution of the nutrition of the cattle mass was distributed in the following way: 57% im proved pasture land, 26% King Grass (CT 115) and 17% sugarcane for animal nutrition. We also took into account soil types in relation to the im pact of physical properties such as soil depth, water holdi ng capacity and drainage capacity on the suitability for production of the various sugarcane varieties. Then we established the following prem ises: to obtain a fodder balance for fattening 1880 head of bulls to a finished live weight of 450 kg, equivalent to 1692 units of greater cattle (UGC), that represent one charge of two cattle per ha. We considered that sugarcane fulfills 43.7% of the requests for foodstuff in the period of minor availability (212 days). Results and discussion Of the 14 variables used for the evaluation of the use of the varie ties of cane as an alternative f or th e f eeding of the c attle, Pr incipal Com ponents Ana lysis indica ted tha t 9 of the variables across three factors cont ributed 64% of the total variat ion (Table 1) and they were considered sufficient in that objective. The proportion of variance explained by top stem s and the stem s of the total biom ass, as well as the genetic resistance to s mut and rust allowed separation of the varieties and allowed recommendation of m ore disease resistant and produc tive varieties than the standard comm ercial clone. In the second com ponent, the digestibility of the dry m atter was ranked as the next m ost important variable (Eigenvector 0.43) after the previous variables. These results explained enough of the variation to allow easy selection of suitable varieties. 2

3 Table 1 Eigenvalues and Eigenvectors from Principal Components Analysis. Factor 1 Factor 2 Factor 3 Eigenvalues % total variance % total variance aggregate Eigenvectors Stems percentage Top stems percentage Digestibility dry matter Brix Pol % Thorns Habit of growth Smut Rust The result of 76.7% of good classif ication from Discriminant Function Analysis (Figure 1) corroborated the im portance of the morphologic and physiological variables that were used in the evaluation of the varieties as possible indicators of the fodder value. The results agree with those of Suárez (2002) who considered varieties to be accep table for the nutrition of cattle if digestibility of dry matter were greater than 50%. Fig. 1 Performance of the groups in Discriminate Function Analysis. Twenty one of the 44 genotypes showed m ore than 50% digestibility of dry matter and tolerance to the principal sugarcane diseases (Table 2). These can be used for animal nutrition (Jorge et al., 2002). Thus a range of suitable varieties of sugarcane are available for commercial production. The dendro gram repres entative of autom atic classif ication of the 21 cultiv ars p resenting higher digestibility of dry matter over 50% allowed the observation of two groups, which passed the threshold of The first (group 2), that included the tester cultivar My5514, was characterised by a higher phenological relation of top and dry leaves than the other group, for which the digestibility was higher (Figure 2). 3

4 Table 2 Characteristics of the 21 varieties that were similar or better than the control variety for digestibility %. Variety DMS IRT Morphologic relation Resistance to diseases SP STP Rust brown Smut C I I B R I C R I C R R Co R R C R R C I R C R R C R R C R R C R R C R I C I I C R I C R R My5514* S R C R R C R R C R R C R I C I R C I R DMS = Digestibility dry matter, IRT= Increment in relation to the control varieties, SP = Stems percentage, STP=Top stems percentage, R= Resistant, I=Intermediate, S = Susceptible, *= Control variety. Fig. 2 Dendrogram of the classification of the cultivars. 4

5 According to Paretas (1990), 40% of the Cuban cattle area is susceptible to drought stress, because of low water holding capacity of the soils, and this contrasts with the 30% of the area that is poorly drained (Figure 3). Nine of the varieties from this study can be used for anim al nutrition in areas of cane production subject to abiotic stress, C89-176, C86-503, C86-12, C86-165, C to drought and C137-81, C86-503, C132-81, C86-12, Co997 for poor drainage, and they are likely to be important in those regions. Fig. 3 Position of the cattle areas in relation to drought and poor drainage. Simulation of zoning agro-ecological The varieties, C86-12 and C132-81, were located in a 40.4 ha area of bad drainage and C in an adjoining 36.1 ha, also with poor draina ge (Figure 4). Areas of 30.3 and 34.2 ha of soils potentially affected by drought were planted to C and C89-176, respectively (Figure 4). Fig 4 Areas planted to varieties based on their adaptation to different stresses. 5

6 Conclusions The percentage of fresh weight of the stem and percentage of the fresh weight of the top stem in sugarcane biom ass, along with resistance to rust and sm ut, were the variables w hich best characterised the studied population for variability in the percentage of dry m atter digestibility. This enabled the selection of varieties for use in the animal nutrition. The classification of the varieties for the percentage of the digestibility of dry matter showed 21 of the 44 varieties had more than 50% digestibility, making them suitable for use in the nutrition of cattle. The agro -ecological zon ing allowed the va rieties to be reco mmended for locations that matched tolerance of drought or waterlogging stresses. REFERENCES FAO (1996). Producción de Alim ento e Impacto Ambiental. Cum bre M undial sobre la alimentación. Vol. II. p 67. FAO-UNESCO (1994). Mapa Mundial de Suelo. Leyenda revisada. FAO. (1998). Agricultura y sus retos. Producción de Alimento e Impacto Ambiental. Vol. I p. 52. Jorge, H., Ibis Jorge, N., Bernal, L. et al. (2002). Avances del program a de Fitomejoramiento en Cuba. Im pacto en la A groindustria Azucarer a. Divers ificación Mem orias Tomo III. Congreso Internacional sobre Azúcar y Derivados de la caña p Kesting, V. (1977). Uber nevere Ergebnisse zur vesbessirung des in vitro methoder zur schazung der verlay lichkeic. Vor- tragstogung des gesellsahfl fyr Er& brung der DDR, Scktion Tierenok- rung, 1,306, Leipzig Paretas, J.J. (1990). Ecosistem as y regionalización de los pastos en Cuba. Instituto de Investigaciones de pastos y Forrajes. MINAGRI, Suárez, O. (2002). Variedades de caña de azúcar para la alimentación del ganado vacuno. Tesis en Opción a Master en Ciencias de la Producción con Rumiantes. 46 p. DIVERSIFICATION DES VARIETES DE CANNE A SUCRE POUR L ALIMENTATION ANIMALE ET LA DURABILITE Par H. JORGE, O. SUÁREZ, H. GARCÍA, I. JORGE et L. BENITEZ Instituto Nacional de Investigaciones de la Caña de Azúcar, Habana,Cuba MOTS-CLES: Alimentation des Bovins, Digestibilité, Matière Sèche, Sols, Le Stress Abiotic. Resume CE PAPIER rela te le s r ésultats d u ne étude su r 44 génotypes de canne à sucre, évalués pour l alimentation animale à l age d e 13 mois en pre mière repousse, à la station territoriale Cienfuegos de recherche sur la canne à sucre de Villa Clara et au centre national de création variétale de Sancti Spiritus à Cuba. 14 traits f urent évalué s a u moyen d analys es multivar iées (Analyses e n composantes principales et discri minante) et une sim ulation de ré gionalisation agro-écologique fut aussi réalis ée. Cette d ernière co ncernait l allocation des variétés se lon le s f acteurs lim itants principaux (sécheresse et faible drainage) sur une ferme d élevage. Les résultats m ontrèrent que les variables, teneurs en eau des tiges (%) et d es sommets (%) avaient une influence importante sur la première composante principale, tandis que la résistance aux maladies (rouille et charbon) avait une 6

7 influence importante sur la seconde composante. On a remarqué que le pourcentage de digestibilité de la m atière sèche pré sentait peu de variab ilité, montrant ainsi une grande stabilité de ce trait. L analyse discrim inante a perm is de class er les va riétés en trois groupes:.des variétés à valeur fourragère faible (en dessous de 40% de digestibil ité de la m atière sèc he), les var iétés à valeu r fourragère intermédiaire (entre 40 % et 50 %) et le s variétés à haute valeur (supérieures à 50% de digestibilité). Les résultats permirent d établir des recomm andations pour 21 nouveaux génotypes caractérisés par leur résistance au x principales m aladies et leur faute valeur fourragère, pour 9 variétés qui étaient supérieure s au tém oin My5514, pour 4 variétés résistantes à l excès d eau et pour 3 variétés résistantes à la sécheresse. La si mulation de la régionalis ation agro-écologique a permis une distribution spatiale des individus appropriés à chaque localité, pour leur digestibilité, leur tolérance à deux stress environnementaux (excès d eau et stress hydrique) et leur résistance aux maladies. DIVERSIFICACIÓN DE LAS VARIEDADES DE CAÑA DE AZÚCAR PARA EL GANADO, ALIMENTACIÓN Y LA SOSTENIBILIDAD Por H. JORGE, O. SUÁREZ, H. GARCÍA, I. JORGE y L. BENITEZ PALABRAS CLAVES: Ganado, Alimentación, Suelos, Estrés Abiótico. Resumen SE PRESENTAN los resultados del estudio de 44 genotipos de caña de azúcar evaluados con meses de e dad en la cepa de retoño en suelos Pardos con carbonato (Ca mbisol eútrico) de la Estación Territorial de la Caña de Azúcar (ETICA) Villa Clara -Cienfuegos y el Centro Nacional de Hibridación de Sancti Spíritus (CNH), con vista a su recom endación para la alimentación anim al. Se evaluaron 14 caracteres m ediante Análisis Multivariado (Componentes Principales y Facto rial Discriminante), también se realizó u na simulación de zonificación ag roecológica para la ubicación de las variedades de caña de azúcar, de acuerd o a los prin cipales factores limitantes (sequía y mal drenaje) de una unidad productora de ganado vacuno. Los resultados reflejan que las variables porcentaje del peso fresco del tallo (% de tallo) y el cogollo (% cogollo) tuvieron una alta influencia en la primera componente, mientras que la resistencia genética a las enfermedades (carbón y roya) lo f ueron para la segun da. Es de destac ar que el porc entaje de diges tibilidad de la m ateria se ca muestra m uy poca v ariabilidad, lo que pued e indicar un a alta estab ilidad de es te c arácter. El Análisis Discriminante permitió clasificar los cultiv ares en tres g rupos: Variedades de bajo v alor forrajero (m enor de l 40 % de la digestibilidad de la m ateria s eca), Variedad es de m edio valo r forrajero (entre 40 50%) y Variedades de alto va lor forrajero (m ayor de l 50%). Los resultados permitieron recom endar 21 nuevos genotipos carac terizados por su r esistencia a las pr incipales enfermedades y su alto valor forrajero, donde 9 de ellas se adaptan a condiciones de estrés ambiental. La sim ulación de la zo nificación a groecológica perm itió la ubica ción espac ial y la modelación en cuanto al correcto establecim iento de los individuos en correspondencia a s u tolerancia con los factores limitantes antes mencionados. 7