I. Dulugeac


RESEARCH CONCERNING THE VARIABILITY AND HERITABILITY OF THE CHIEF MORPHOLOGICAL TRAITS OF THE EQUINE POPULATION IN THE AREA OF THE PRAHOVA COUNTY

I. Dulugeac, V. Ujică

Abstract
The heritability, as a characteristic of any measurable feature, is one of the most important indicators concerning the decisions to be made in the process of genetic improvement of the horse population. The studies and the researches undertook by several authors on the horse breeds in our country, although few in numbers and spaced in time, are marking a fairly large amplitude of characters and features inside each population, with the presence of individuals who’s performances proving large capabilities of improvement regarding the corporal massivity as well as speed. The analysis of the heritability coefficients and of existing differences between coefficients’ values, made by comparing the different studied subpopulations, are leading to the conclusion that the horse population in the area of Prahova county is formed of several structural biological units differentiated from one another by the genotype that forms them and that behaves differently as to the potentiality of the hereditary transmission of different morphological features. When the genetic variability is expressed in terms of heritability coefficient, it results that the highest values within the analysed populations were obtained for the following features: trunk oblique length (h2=0.43), thorax perimeter (h2=0.46), thorax width (h2=0.57), loin width at the hips’ level (h2=0.39), cannon perimeter (h2=0.43), back length (h2=0.47), humerus length (h2=0.44), femur length (h2=0.47). The stronger determination of the hereditary variation for these features are evidentiating the reduced influence of the environmental factors and the high rate of genetic determination of the above mentioned features’ variability. One can consider that the actions of genetic improvement within the analysed lots were carried on in the sense of hereditary fixation of characters that determine body massivity and enhancement of energetic capacity, that the higher genetic variability of this population insures a rapid effect of the selection and a higher probability of success in obtaining body massivity by selection.

Key words: equine, measurable features, heritability, genetic improvement


CERCETĂRI PRIVIND VARIABILITATEA ŢI HERITABILITATEA PRINCIPALELOR ÎNSUŞIRI MORFOLOGICE ALE POPULAŢIEI DE CABALINE DIN AREALUL JUDEŢULUI PRAHOVA

I. Dulugeac, V. Ujică

Rezumat
Heritabilitatea, ca o caracteristica a fiecarui caracter masurabil, este unul dintre cei mai importanti indicatori în ceea ce priveste deciziile care urmeaza sa fie realizate în procesul de ameliorare genetica a populatiei de cabaline. Studiile si cercetarile întreprinse de mai multi autori pe rase de cai din tara noastra, desi putini la numar si de departe în timp, marcheaza o amplitudine destul de mare de caractere si caracteristici în interiorul fiecarei populatii, cu prezenta indivizilor a caror performante atesta capacitatile mari de îmbunatatire în ceea ce priveste masivitate corporala, precum si viteza. Analiza coeficientilor de heritabilitate si diferentele existente între valorile coeficientilor, facute prin compararea diferitelor subpopulatii studiate, conduc la concluzia ca populatia cai din zona judetului Prahova este formata din mai multe unitati biologice structurale, diferentiate de una de alta prin genotipul care le formeaza si care se comporta diferit în ceea ce priveste potentialitatea transmiterii ereditare a diferitelor caracteristici morfologice. Atunci când variabilitatea genetica este exprimata în termeni de coeficient de heritabilitate, rezulta ca cele mai mari valori în cadrul populatiilor analizate au fost obtinute pentru urmatoarele caracteristici: lungimea oblica a trunchiului (h2 = 0,43), perimetrul toracelui (h2=0,46), largimea toracelui (h2=0,57), largimea crupei la solduri (h2=0,39), perimetrul fluierului (h2=0,43), lungimea spatelui (h2=0,47), lungimea humerusului (h2=0,44), lungimea femurului (h2=0,47). Determinarea puternica a variatiei ereditare pentru aceste caracteristici, evidentiaza influenta redusa a factorilor de mediu si rata ridicata de determinare genetica a variabilitatii caracterelor mentionate mai sus. Se poate considera ca actiunile de ameliorare genetica în loturile analizate au fost desfasurate în sensul de fixare ereditara a caracterelor care determina masivitatea corporala si îmbunatatirea capacitatii energetice, deoarece variabilitatea genetica mai mare a acestei populatii asigura un efect rapid a selectiei si o probabilitate mai mare de succes în obtinerea masivitatii corporale prin selectie.

Cuvinte cheie: ecvine, caractere cantitative, heritabilitate, ameliorare genetica