Pollen Viability in Eggplant Using Colorimetric and In vitro Techniques

Abstract

The causes of fruit abortion, in eggplants, may be related to the absence of viable pollen under high temperatures, common in the Northeast region of Brazil, resulting in a reduction in the number of fruits per plant and consequently in productivity. The objective of this study was to evaluate the techniques of identification of PV – pollen viability in eggplant, as well as to correlate these results with the FFI – Fruit Fixation Index, NFP – Number of Fruits per Plant and PP – Production per Plant obtained in cultivation under high temperatures. The experiment was conducted at the Federal Rural University of Pernambuco, Recife, Brazil, between September and December 2017. The experiment design was a randomized block design with four replications, in the 7 x 4 factorial scheme (7 genotypes x 4 evaluation of PV) containing four plants per experimental plot. The results showed that the different techniques used detected viable pollens in the genotypes evaluated in smaller and in larger proportions. The highest percentages were observed in the treatments with CA – Carmine Acetic and AS – Alexander Solution and these overestimated the PV (>90%). In the test with TTC – 2,3,5-triphenyltetrazolium chloride (25%), the viability estimation was equivalent to the in vitro germination test, however the genetic correlations were null and/or very low between these techniques and the FFI, NFP and PP traits. The genetic correlations between the results obtained with CA and AS with FFI, NFP and PP under conditions of high temperatures were high and positive and suggest that the selection based on PV only, except with the use of TTC solution, may be efficient for indirect selection of genotypes with high FFI, NFP and PP.

Combining capacity and heterosis in eggplant hybrids under high temperatures

“…Although the percentages of PV, FFI, NFP and PP were close to or below the values reported by other authors (Silva et al, 1999;Baswana et al, 2006;Valadares et al, 2019), the averages obtained for hybrids and genitors were superior to those obtained for Ciça in most traits, except for FWe, FL and PH, where Ciça stood out among the best genotypes (Table 3).…”

“…Regarding the effects of SCA, the 1x4, 1x7 and 2x5 hybrids showed nonadditive gene effects for FFI, NFP and PP, although negative for FWe, due to the negative genetic correlation between FWe and the other traits (Valadares et al, 2019) (Table 1).…”

“…However, only 1x4 hybrid stood out with the highest averages for PV, FFI, NFP and PP (Table 2). FFI is the trait most influenced by high temperatures in the Northeast Brazil, because under high temperatures it is drastically reduced, beside that it has a genetic correlation with the traits NFP and PP (Valadares et al, 2019).…”

“…In order to obtain F1 hybrids, 7 parents from the Embrapa Hortaliças Eggplant Germplasm Bank and previously selected (Valadares et al, 2019) were crossed in a 3x4 partial diallel arrangement, totaling twelve hybrid combinations.…”

“…In northeastern Brazil, especially when flowering coincides with the hottest period of the year, high temperatures have been a limiting factor for productivity, increasing the occurrence of malformation and/or fruit abortion, especially on crops under greenhouse conditions, where internal temperatures are higher than the outside one, causing a considerable reduction on crop yield in the region (Valadares et al, 2019). It is therefore important that high temperature tolerant eggplant strains and hybrids are obtained and evaluated under such conditions.…”