Expression of self-incompatibility in Coffea canephora genotypes grown in the western Amazon

Abstract

The objective of this work was to characterize the expression of gametophytic self-incompatibility in a Coffea canephora breeding population, to assist in the management and development of new cultivars. For that purpose, 550 in vitro pollinations were carried out among 62 parent plants, of which 27 were from the conilon botanical variety and 35 from the robusta. Thirty-two genotypes compatible with all previously known testers were identified, suggesting the existence of new compatibility groups. From these results, hybridizations were carried out in a complete diallel design with reciprocal crosses to characterize new test plants. Based on the compatibility response with the test plants, the genotypes were clustered into the six following groups: group I, 11 (17.74%) genotypes; group II, 13 (20.97%); group III, 6 (9.68%); group IV, 9 (14.52%); group V, 8 (12.90%); and group VI, 15 (24.19%). The genotypes of the botanical variety robusta show a higher frequency of plants in compatibility group VI and a greater genetic variability, whereas those of the conilon variety have a higher frequency of plants in compatibility group II. The identification of new compatibility groups assists in new management practices that seek to increase the efficiency of pollination by favoring, through natural means, fully compatible crosses.

Dynamic of dry matter accumulation in berry, bean, and husk of six Coffea canephora genotypes during fruit maturation

“…Considering only the fully ripe berries, the Pirata, A1, Clementino and Beira Rio 8 genotypes had the elevated DM performances (~50%), while P1 (late maturation cycle) and Bamburral (medium cycle) were characterized with even higher values, above 60%, similarly already shown by one similar parameter, percentage of beans in berries 34 . Although the selfincompatibility is an important trait for plant populations of C. canephora, this trait should be managed to avoid the reduction of e ciency of plant pollination, which affects yield in coffee elds 35 . Considering that DM accumulation and bean yield were in uenced by the maturation cycle of the genotypes, it could be recommended a crop organization in rows for the different genotypes, starting with the early cycle genotypes and ending with the late cycle ones, facilitating the manual or semi-mechanized harvesting operations/management.…”

“…The accumulation of dry matter in the berries increased as the maturation progressed, attaining the highest values in the nal weeks of maturation process: 45-47 WAF for Beira Rio 8, A1, Pirata Bamburral and Clementino, (early/medium and medium maturation cycle genotypes), and 49 WAF for late maturation P1 genotype. The DM accumulation was initially the highest for berry and bean DM per berry (33)(34)(35)(36)(37)(38)(39)(40)(41), while the highest increases in husk DM accumulations happened latterly (41)(42)(43)(44)(45)(46)(47)(48)(49). High late husk DM investments can be related to necessity of the embryo protection, as one theme for eventual future research.…”

“…Second order polynomial regression for the berry FM to bean DM ratio of six genotypes (Pirata, Bamburral, A1, Clementino, Beira Rio 8 and P1) of Coffea canephora collected from end of berry expansion to full maturation (33,35,37,39,41,43,45,47 and 49 weeks after owering). Lower-case letters compare time effect inside each genotype, whilst upper-case letters compare genotype effect in each sampling time the by Tukey's test at 5% probability, while Pvalues in bold indicate signi cant statistical difference (n=5).…”

“…Bean and husk percentage in dry mass of one berry of six genotypes (Pirata, Bamburral, A1, Clementino, Beira Rio 8 and P1) of Coffea canephora collected from end of berry expansion to full maturation (33,35,37,39,41,43,45,47 and 49 weeks after owering shown in external radius of the chart). For each genotype lower-case letters compare sampling time effect inside bean and husk percentage, whilst upper-case letters compare bean and husk percentage effect in each sampling time by Tukey's test at 5% probability, while the p-values in bold indicate statistical difference of interaction (n=5).…”

“…For percentage of bean and husk in berry, the data were submitted to two-way ANOVA (percentage of each component x time of collection) considered a mixed linear model ('nlme' package) and maximum likelihood to test the signi cance of differences between the accumulated mass of two berry parts (bean and husk), for each of the nine sampling times (33,35,37,39,41,43,45, 47 and 49 WAF). In gure with bean and husk percentage in dry mass of one berry, only interaction p-value was considered once the factors were not independently compared 44,45 , trying to make the presentation the clearest possible.…”