Temperature Effect on Traditional Pear (Pyrus communis L.) Landraces Seed Germination

Investigations included six traditional pear landraces (Pyrus communis L.): Aleksandra, Vodenka, Patlidjanka, Ljubichica, Tatlikuti and Crvenushka. The number of seeds per fruit, seed energy and total seed germination were investigated and statistically analysed (P = .05 and P = .01). Seed stratification encompassed pre-chilling by using three treatments: I treatment covers seed pre-chilling at -18°C for 24 hours; II treatment covers seed pre-chilling at +1°C for 2 weeks; III treatment covers seed pre-chilling at +8°C for 1 week. Only Patlidjanka belongs to the group with high seed number in the fruit. The other landraces produced low seed number like 2-3 seeds per fruit. The average number of all researched landraces is 3.67 seeds per fruit. The pear Tatlikuti showed a very high significant difference (P = .01). It was concluded that III treatment showed the highest seed energy at landraces Ljubichica 77.5% and Tatlikuti 75.0% and the lowest at Aleksandra 52.5%. There were significant differences (P = .05) between the applied treatments regarding seed energy. In II treatment, the total seed germination had the highest effect on Patlidjanka 87.75%. The values for germination seeds in the other landraces were in the range of 77.5% to 86.25%. Statistically, a significant difference was determined in the landraces Ljubichica and Crvenushka (P = .05), and there was high significant difference (P = .01) in the pear Aleksandra. The II and III treatments could be recommended as the most suitable to improve the pear seed germination.

Influence of rootstocks on growth, yield, fruit quality and leaf mineral element contents of pear cv. 'Santa Maria' in semi-arid conditions

BACKGROUND: Rootstocks play an essential role to determining orchard performance of fruit trees. Pyrus communisand Cydonia oblonga are widely used rootstocks for European pear cultivars. The lack of rootstocks adapted to different soil conditions and different grafted cultivars is widely acknowledged in pear culture. Cydonia rootstocks (clonal) and Pyrus rootstocks (seedling or clonal) have their advantages and disadvantages. In each case, site-specific environmental characteristics, specific cultivar response and production objectives must be considered before choosing the best rootstock. In this study, the influence of three Quince (BA 29, Quince A = MA, Quince C = MC) and a local European pear seedling rootstocks on the scion yield, some fruit quality characteristics and leaf macro (N, P, K, Ca and Mg) and micro element (Fe, Zn, Cu, Mn and B) content of 'Santa Maria' pear (Pyrus communis L.) were investigated. RESULTS: Trees on seedling rootstock had the highest annual yield, highest cumulative yield (kg tree(-1)), largest trunk cross-sectional area (TCSA), lowest yield efficiency and lowest cumulative yield (ton ha(-1)) in the 10th year after planting. The rootstocks had no significant effect on average fruit weight and fruit volume. Significantly higher fruit firmness was obtained on BA 29 and Quince A. The effect of rootstocks on the mineral element accumulation (N, K, Ca, Mg, Fe, Zn, Cu, Mn and B) was significant. Leaf analysis showed that rootstocks used had different mineral uptake efficiencies throughout the early season. CONCLUSION: The results showed that the rootstocks strongly affected fruit yield, fruit quality and leaf mineral element uptake of 'Santa Maria' pear cultivar. Pear seedling and BA 29 rootstock found to be more prominent in terms of several characteristics for 'Santa Maria' pear cultivar that is grown in highly calcareous soil in semi-arid climate conditions. We determined the highest N, P (although insignificant), K, Ca, Mg, Fe and Cu mineral element concentrations on the pear seedling and BA 29 rootstocks. According to the results, we recommend the seedling rootstock for normal density plantings (400 trees ha(-1)) and BA 29 rootstock for high-density plantings (800 trees ha(-1)) for 'Santa Maria' pear cultivar in semi-arid conditions.

Cultivares e portaenxertos sobre o vigor de plantas de pereira europeias / Cultivars and rootstocks on plants vigor of European pear

A cultura da pereira (Pyrus communis) possui grande potencial de expansão no sul do Brasil devido às condições climáticas e solo. A carência de informações a respeito da(s) melhor(es) combinação(ões) de cultivares copa de pereira europeia e portaenxertos, quanto ao aspecto vegetativo e potencial produtivo, tem limitado o cultivo. O objetivo do trabalho foi avaliar a influência de cultivares copa de pereira europeia e portaenxertos de marmeleiro (Cydonia oblonga) sobre o vigor e variáveis de plantas. Os experimentos foram conduzidos em pomares comerciais da cidade de Fraiburgo, Estado de Santa Catarina, durante os ciclos de cultivo 2008/09, 09/10 e 10/11. As cultivares avaliadas foram 'Packham's Triumph', 'Santa Maria', 'Rocha' e 'Abbè Fetel' e os portaenxertos de marmeleiro EMC e Adams. O espaçamento de plantio foi de 0,3m entre plantas e 4m entre linhas. As variáveis analisadas foram: a. incremento de altura de plantas (m); b. incremento de volume de copa (m³); c. incremento de diâmetro do tronco da cv. 'copa' (mm); d. incremento de diâmetro do tronco do portaenxerto (mm); e. diferença de diâmetro do tronco entre a cultivar copa e o portaenxerto (mm); f. índice de fertilidade (no de gemas cm-1); g. massa fresca média total acumulada do material vegetativo das três podas de inverno (kg); h. diferença cumulativa entre a massa fresca e a massa seca dos ramos podados (kg). As diferentes combinações de cultivares e portaenxertos interferiram nas diferentes variáveis analisadas. As combinações Abbè Fetel e Rocha sobre marmelo Adams, foram significativamente mais vigorosas em termos de incremento de diâmetro do tronco da cultivar copa, incremento de altura de plantas, incremento de volume de copa e massa fresca média total acumulada do material vegetativo das podas de inverno dos três anos. A combinação Santa Maria sobre marmelo Adams apresentou vigor intermediário significativo de plantas de acordo com o incremento em volume de copa, diferença de diâmetro do tronco entre a cultivar copa e do portaenxerto, sendo mais indicada para uso comercial, devido ao maior equilíbrio proporcionado entre parte vegetativa e produtiva da planta, nas condições edafoclimáticas experimentais do Sul do Brasil.

The pear (Pyrus communis) culture offers a great expansive market opportunity in southern Brazil, according to climatic conditions and soil. However, there are still some barriers that prevent satisfactory economic production, such as lack of knowledge about the best combinations of cultivars and rootstocks. The objective of the study was to evaluate the influence of European pear cultivars and quince (Cydonia oblonga) rootstocks on the plants vigor variables. The experiments were carried out in commercials orchards in Fraiburgo Municipality, Santa Catarina state, during the crop season of 2008/09, 09/10 and 10/11. The cultivars evaluated were 'Packham's Triumph', 'Santa Maria', 'Rocha' and 'Abbè Fetel' and the quince rootstocks EMC and Adams. The cultivars and rootstocks combinations were conducted in a spacing of 0.3mx4m between plants and rows, respectively. The vigor variables evaluated were, a. plants height increment (m); b. canopy volume increment (m³); c. truck diameter increment of the cultivars canopy (mm); d. truck diameter increment of rootstocks (mm); e. difference between the trunk diameter of cultivars canopy and rootstock (mm); f. fertility index (buds cm-1); g. total cumulative average of fresh weight of pruned branches (kg); and h. cumulative difference between the fresh and dry weight of pruned branches (kg). All combinations evaluated affected the vegetative parameters of the European pear cultivars. The combinations Abbè Fetel and Rocha grafted on Adams quince rootstocks are significant more vigorous according to increment of cultivars canopy truck diameter, plant height increment, cultivars canopy volume increment and cumulative average weight of pruned branches, when compared with others combinations. The combination Santa Maria grafted on Adams quince rootstock showed significant intermediate vigor according to cultivar canopy volume increment, truck diameter of cultivar canopy and, truck diameter of rootstock. This combination presented a better proportion amongst the vigor variables and can be indicated for commercial production according to the experimental edafoclimatic conditions of southern Brazil.

Influence of cultivar and rootstock on early growth and syllepsis in nursery trees of pear (Pyrus communis L., Rosaceae)

A two-year field study was conducted to examine the capacity of spontaneous formation of long sylleptic shoots (LSS) in nursery trees of pear cvs. 'Abbé Fétel', 'Conference' and 'Starking Delicious' grafted on Quince MA (MA) and Quince BA 29 (BA 29) rootstocks in a nursery during the first year after bud grafting. Tree height (TH), trunk diameter (TD) - 10 cm above the bud union and number of LSS were measured at the end of each season. The TH was measured from the ground level. The highest number of LSS was developed by cv. 'Abbé Fétel' in both the seasons, and the lowest by cv. 'Starking Delicious'. Tree height and TD were highly significantly affected by the cultivar in both the years and by the rootstock in 2008. The interactions between them did not significantly affect the examined parameters. The study showed that the early growth and syllepsis of pear nursery trees during the first year after bud-grafting were incomparably more affected by the cultivar than by the rootstock under similar weather conditions and on the same soil in a crop rotation system.