Melhoramento do cafeeiro. VIII - Novas determinações sôbre poliembrionia, sementes sem embrião e lojas dos frutos sem sementes em Coffea
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1955-12
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Instituto Agronômico (IAC)
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No presente trabalho são apresentadas observações sôbre a freqüência de várias anomalias encontradas em frutos e sementes de diversas variedades de Coffea arabica, em C. canephora, C. Dewevrei, C. congensis, C. liberica e em alguns híbridos interespecíficos. C. arabica var. typica foi considerada como padrão nas comparações realizadas no grupo de variedades dessa espécie. De um modo geral as sementes poliembriônicas apresentam dois embriões. No entanto, algumas sementes com três embriões foram também achadas, porém com freqüência mais reduzida. Observou-se 1,19% de sementes poliembriônicas na var. typica, enquanto a incidência dêste tipo de sementes foi de 3,47% para a var. angustifolia e 3,16% para a var. erecta. Proporções muito reduzidas de sementes poliembriônicas foram encontradas em C. canephora (café Robusta), C. congensis (Congensis Bangelan) e no híbrido tetraploide C. arabica x C. Dewevrei (cafeeiro 387). Sementes sem embrião foram achadas com maior freqüência no Caturra Amarelo, Cêra, Goiaba Amarelo e Nana, e no café Kouillou (C. canephora), Congensis Bangelan, C. Dewevrei e no híbrido interespecífico C. liberica x C. Dewevrei. A alta freqüência de sementes sem embrião no Caturra Amarelo é limitada a um cafeeiro, C 476-15, e a algumas plantas de sua progênie. Êste característico provavelmente é hereditário. Verificou-se que a var. typica de C. arabica apresenta 0,21% de lojas do fruto com falsa poliembrionia. As porcentagens correspondentes para o Mundo Novo, Bourbon Amarelo e Mokka foram de 5,34, 4,97 e 4,91, respectivamente. Em C. congensis (Bangelan) e C. Dewevrei, esta anomalia foi encontrada com alta freqüência. A falsa poliembrionia é responsável pelas sementes "concha", as quais podem se formar em frutos com um, dois ou três lóculos desenvolvidos. A freqüência de lojas vazias, sem sementes, foi de 6,60% para a var. typica, enquanto o café Mundo Novo e a var. erecta apresentaram 29,50 e 30,00%, respectivamente. Entre as outras espécies, C. Dewevrei, C. canephora (Robusta) e C. liberica x C. Dewevrei apresenta incidência maior desse defeito. Sementes moca ocorrem com freqüência variável nas variedades de C. arabica : é baixa em C. Dewevrei e mais elevada para C. canephora, C. congensis e nos híbridos arabica x Dewevrei e liberica x Dewevrei. A freqüência de sementes oriundas de frutos triloculares é mais elevada nas variedades de C. arabica, purpurascens, semperflorens, mokka e Bourbon Amarelo. Proporções muito elevadas dêste tipo de sementes foram encontradas para algumas variedades de C. Dewevrei.
It is known that seeds with more than one embryo (polyembryonic) as well as germless seeds are found to occur in the cultivated species of Coffea. Fruits with more than one seed per locule (false polyembryony) or fruit locules without normal seeds are also found as well as fruits with only one developed locule (peaberry seeds), or trilocular fruits presenting three seeds. This paper presents the observations made on the frequencies of these abnormalities in several varieties of C. arabica, in C. canephora, C. Dewevrei, C. congensis and C. liberica and also in some interspecific hybrids. C. arabica var. typica was considered as a standard in comparisons made among arabica varieties. As a rule, polyembryonic seeds present two embryos. However, seeds with three normal embryos were also found with very low frequency. It vas observed that 1.19 per cent of polyembryonic seeds occurred in var. typica, while the incidence of this type of seed was 3.47 per cent for var. angustifolia and 3.16 per cent for var. erecta. For other species than arabica very reduced proportions of polyembryonic seeds were found in C. canephora (Robusta coffee), C. congensis (Congensis Bangelan) and in a tetraploid hybrid C. arabica x C. Dewevrei (plant number C 387). Germless seeds were more frequently found in Yellow Caturra, Cera, Yellow Goiaba and Nana, among arabica varieties, and in Kouillou (C. canephora) Congensis Bangelan (C. congensis), C. Dewevrei and in the interspecific hybrid C. liberica x C. Dewevrei. The higher frequency of germless seeds in the Yellow Caturra was limited to a single plant, C. 476-15 and to a few plants in its progeny. This is probably an inherited character. It was observed that typica variety of C. arabica presents 0.21 per cent of fruit locules with false polyembryony. The corresponding percentages for Mundo Novo, Yellow Goiaba and Mokka were 5.34, 4.97, and 4.91 per cent, respectively. In C. congensis Bangelan and C. Dewevrei this abnormality is also found with high frequency. False polyembryony is responsible for the commercial seed type called "elephant bean", which may be formed in fruits with one, two or three developed locules. The frequency of empty fruit locules was 6.60 per cent for typica while Mundo Novo and var. erecta presented 29.50 per cent and 30.00 per cent respectively. Among the other species, C. Dewevrei, C. canephora (Robusta) and C. liberica x C. Dewevrei presented higher incidences of empty fruit locules. The frequencies of peaberry seeds were variable for the arábica varieties, low for C. Dewevrei, and high for C. canephora, C. congensis and the hybrids arabica x Dewevrei and liberica x Dewevrei. Seeds from trilocular fruits were found with higher frequencies in the arábica varieties purpurascens, semperflorens, mokka, and Yellow Bourbon. Unusually high proportions of this seed type were found in certain varieties of C. Dewevrei.
It is known that seeds with more than one embryo (polyembryonic) as well as germless seeds are found to occur in the cultivated species of Coffea. Fruits with more than one seed per locule (false polyembryony) or fruit locules without normal seeds are also found as well as fruits with only one developed locule (peaberry seeds), or trilocular fruits presenting three seeds. This paper presents the observations made on the frequencies of these abnormalities in several varieties of C. arabica, in C. canephora, C. Dewevrei, C. congensis and C. liberica and also in some interspecific hybrids. C. arabica var. typica was considered as a standard in comparisons made among arabica varieties. As a rule, polyembryonic seeds present two embryos. However, seeds with three normal embryos were also found with very low frequency. It vas observed that 1.19 per cent of polyembryonic seeds occurred in var. typica, while the incidence of this type of seed was 3.47 per cent for var. angustifolia and 3.16 per cent for var. erecta. For other species than arabica very reduced proportions of polyembryonic seeds were found in C. canephora (Robusta coffee), C. congensis (Congensis Bangelan) and in a tetraploid hybrid C. arabica x C. Dewevrei (plant number C 387). Germless seeds were more frequently found in Yellow Caturra, Cera, Yellow Goiaba and Nana, among arabica varieties, and in Kouillou (C. canephora) Congensis Bangelan (C. congensis), C. Dewevrei and in the interspecific hybrid C. liberica x C. Dewevrei. The higher frequency of germless seeds in the Yellow Caturra was limited to a single plant, C. 476-15 and to a few plants in its progeny. This is probably an inherited character. It was observed that typica variety of C. arabica presents 0.21 per cent of fruit locules with false polyembryony. The corresponding percentages for Mundo Novo, Yellow Goiaba and Mokka were 5.34, 4.97, and 4.91 per cent, respectively. In C. congensis Bangelan and C. Dewevrei this abnormality is also found with high frequency. False polyembryony is responsible for the commercial seed type called "elephant bean", which may be formed in fruits with one, two or three developed locules. The frequency of empty fruit locules was 6.60 per cent for typica while Mundo Novo and var. erecta presented 29.50 per cent and 30.00 per cent respectively. Among the other species, C. Dewevrei, C. canephora (Robusta) and C. liberica x C. Dewevrei presented higher incidences of empty fruit locules. The frequencies of peaberry seeds were variable for the arábica varieties, low for C. Dewevrei, and high for C. canephora, C. congensis and the hybrids arabica x Dewevrei and liberica x Dewevrei. Seeds from trilocular fruits were found with higher frequencies in the arábica varieties purpurascens, semperflorens, mokka, and Yellow Bourbon. Unusually high proportions of this seed type were found in certain varieties of C. Dewevrei.
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ALVES, A. Melhoramento do cafeeiro. VIII - Novas determinações sôbre poliembrionia, sementes sem embrião e lojas dos frutos sem sementes em Coffea. Bragantia, Campinas, v. 14, n. 27, p. 285-300, 1955.