Dialell Analysis for Morphoagronomic Descriptors in Physalis Angulata L. Hybrids

Physalis angulata L. is an American species with edible fruits that stands out for having high nutritional and pharmaceutical value. The species is found in almost the entire Brazilian territory but the consumption of its fruits is not widespread. Genetic improvement is one of the main factors that can make P. angulata a crop in Brazil. The aim of this work was to evaluate the existence of heterosis and heterobeltiosis for morphoagronomic descriptors, to estimate correlations, and to select the best hybrids in P. angulata in a full diallel with ve accession. Twenty plant, fruit and seed descriptors were evaluated, and plant height and total soluble solids showed signicant genetic variation. Positive heterobeltiosis for total soluble solids was observed in hybrids Pi x G53, Can x Pi and Can x LG, while negative heterobeltiosis for plant height was observed in G53 x LG, Pi x Laj e Can x Laj hybrids. Heterosis was also observed for both descriptors. Using selection indexes, Can x G53, Can x LG, Pi x G53, Can x Pi and G53 x Pi were selected as the best hybrids, expressing smaller plant height and higher total soluble solids. to populations with more variability (Mendonça et al. 2002). Considering this, hybrid Can x G53 have the higher potential to develop P. angulata populations with high mean and variability. The occurrence of heterosis and heterobeltiosis in our study suggests that the use of hybrids in P. angulata must be considered aiming to increase yield and quality fruit traits. Additionally, the best hybrids can be used to produce segregating populations which can be applied to proceed genetic breeding or to make genetic studies. This is the rst report of diallel analysis and occurrence of additive and non-additive effects in P. angulata traits. Further studies are needed to nd the best conditions for evaluating P. angulata germplasm, especially for fruit traits. Heterosis and heterobeltiosis were observed in P. angulata hybrids for plant height and total soluble descriptors. Plant height was negative correlated to fruit traits. The use o hybrids showed good perspectives in P. angulata breeding. Can x G53, Can x LG, Pi x G53, Can x Pi and G53 x Pi was considered the best hybrids for both plant height and total soluble solids, and can be used to develop segregating populations.


Introduction
The Physalis genus is easily recognized due its peculiar morphology, mainly in fruiting, when the species of the genus are characterized by the occurrence of an in ated calyx which evolves and protect the hole fruit. The name Physalis has Greek origin, and the term "Physa" are related to the persistent calyx evolving the fruits, meaning bubble or bladder. Mexico is considered the center of diversity of Physalis and two thirds of the species of the genus are endemic of this region (Rufato et al. 2013).
Physalis angulata L. is one of the most representative species of Physalis genus. In Mexican regions, the species develops since zero to 2.400 meters above the sea along the margins of decidual tropical forests, and also as weeds in cultivated areas, pastures and pine forests (Vargas-Seeds of each accession were sown in seedling bags containing soil and vegetable substrate in 2:1 proportion in greenhouse. The humidity of the substrate was maintained by spray irrigation. After 20 days the seedlings were transferred to 8-liter pots containing the same proportion of soil and vegetable substrate, and maintained in greenhouse. Fertilization was adapted based on the cherry tomato crop recommendation (Silva et al. 2006), using 28 g of super simple phosphate, 8.5 g of potassium chloride and 4.5 g of urea (the latter in two applications).
The crossings were conducted in the rst hours of the day and were started by protecting the owers in ower bud phase. For the emasculation, the llets were removed using stainless forceps sterilized with ethanol 70%. The stigmas were manually pollinated and the owers were identi ed and protected with woven bags. All the combinations between the ve accessions were conducted including the reciprocals. The mature fruits were collected, washed and pulped. The seeds were collected, dried in lter paper at environmental temperature and stored in paper bags in glass jars containing silica gel at 8º C.

Evaluation of the diallel
The experiment was conducted in August to December 2019. The diallel was composed of 23 treatments, including ve parents, nine hybrids and nine reciprocals (seeds of LG x Pi and Pi x LG were not obtained). Seeds of each F 1 , reciprocal and parents were sown at the same conditions above. When the seedlings reach about 25 centimeters, they were transferred to pits in experimental eld at Horto Florestal/UEFS in a randomized block design with three repetitions and experimental plot of four plants with spacing of one meter between lines and 0.5 meters between plants.
The pits were previously fertilized as above and irrigated two times a day by drip irrigation.
The plants were evaluated with the follow descriptors based on the descriptors proposed by the Universidade Nacional da Colômbia for P. peruviana (González et al. 2008).
-Calyx color (CC) and stem color (SC): green without anthocyanin, green with little anthocyanin or green with strong anthocyanin.
-Calyx shape (CS): elongated, slightly attened or attened. -Days to owering (DF), from the day of sowing to the complete opening of the rst ower.
-Longitudinal (LFL) and transversal (TFL) fruit length, measured from ve random fruits per plant using a digital caliper, in millimeters.
-Number of fruits per plant (NFP), manually counting the number of fruits from each plant, counted in the physiological maturity stage.
-Plant height (PH), measured from the base to until the beginning of the meeting of the secondary branches at 45 days after sowing, using a measuring tape, in centimeters.
-Stem diameter (SD), measured ve centimeters above the ground at 45 days after sowing using a digital caliper, in millimeters.
-Total soluble solids (TSS), measured in the physiological maturity stage from ve random fruits per plant using a digital refractometer, in ºBrix.
-Weight of fruits per plant (WFP), weighing all the fruits from each plant, measured in the physiological maturity stage using a precision balance, in grams.
-Weight of seeds per fruit (WSF), measured in the physiological maturity stage from three random fruits per plot, using a precision balance, in milligrams.
-Number of seeds per fruit (NSF), by the expression NSF = WSF / W100) x 100, where W100 is the weight of 100 seeds.

Statistical analysis
The averages of each experimental plot were used to obtain the variance components by restricted maximum likelihood (REML), and the genetic effects of the parents, GCA and SCA by using the model 36 of software SELEGEN-REML/BLUP (Resende 2016). Spearman coe cients of correlation between the descriptors were calculated using the software Genes (Cruz 2013), using the predicted genetic values estimated by using the model 21 of software SELEGEN-REML/BLUP (Resende 2016).
Heterosis and heterobeltiosis were calculated by the following formulas: Heterosis (%) = [( F 1 -P ) / P ] x 100 Were F 1 is the value of the hybrid/reciprocal, P is the average of the parents, and P B is the value of the best parent, based on the descriptor.
Selection indexes using the models Additive and Mulamba-Rank were calculated to select the best hybrids, using the software SELEGEN-REML/BLUP (Resende 2016).

Results And Discussion
Genetic variation and parameters Nine of the twenty descriptors evaluated show no variation between the experimental plots (CC, CS, CSC, GH, LAS, LBS, LLS, LMS, SC) and were discarded from the statistical analysis. The descriptors evaluated in this study were adapted from P. peruviana (González et al. 2008), once there is no o cial descriptors list for P. angulata. Despite the similarities and phylogenetic proximity between P. peruviana and P. angulata, this could be the cause of the lack of variation of these descriptors. Between the eleven descriptors submitted to Deviance Analysis, PH and TSS showed signi cant genetic variability at 1% and 5% of probability, respectively (Table 1), indicating that these traits have potential for genetic breeding.
The relative high values of residual variance found in many of the descriptors evaluated in this study (Table 1) could be due to high environmental interference, including for PH and TSS. There was observed considerable variance within plots and this can be explained due to the species had not yet undergone genetic improvement and there is still no well-established crop system. Moreover, despite P. angulata is considered a selfpollinated species (Menzel 1951 Our results showed that P. angulata fruits can almost reach the SSC values of P. peruviana, even that the accessions of this study did not pass through genetic improvement.
Although there was no signi cant genetic variation for NFP and WFP, two important traits related to fruit yield, there were a high phenotypic variation between treatments. NFP varied from 90.55 to 316.53 and WFP varied from 107.57 g to 483.16 g. Considering the row spacing used in this study, we could estimate yields varying from 2151 kg.ha -1 to 9663 kg.ha -1 .
Information about crop systems in P. angulata are still incipient and the absence of good control of the environment can elevate the residual variance. Besides that, the species has not yet been domesticated (Souza et al. 2016), and the possibility that the accessions may not be homozygous can also increase residual variance. So, we believe that there is genetic variance between the accessions but new experiments need to be proceeded for evaluate this variation.
High genetic variation for yield traits have been found in P. peruviana (Herrera et al. 2011;Kumar et al. 2017), indicating a potential to produce more than 15 t.ha -1 (Herrera et al. 2011) . Using the maximum value of WFP found in our studies, we found that some plots reached potential yields of 16 t.ha -1 of fruits, with the hybrid Can x Laj reaching 9.3 t.ha -1 , on average, reinforcing the potential of P. angulata to be a Brazilian crop. It is important to mention that to reach those high yields in crop conditions, not only genetic breeding but the establishment of the ideal crop system for the culture is necessary.
We found broad-sense heritabilities 0.53 and 0.41 for PH and TSS, respectively (Table 1) Evaluating GCA and SCA, we considered negative values to be ideal for PH, since this descriptor was negative correlated with yield traits.
Accessions LG, Can and G53 showed negative GCA for PH, and seven hybrids showed negative SCA (Table 4). Regarding to TSS, we considered positive values to be ideal, since high TSS values are associated to the sweetness of the fruits, a trait which best suits the fruit market. Accessions Can, Pi and G53 showed positive GCA for TSS, and ten hybrids showed positive SCA. The accessions Can and G53 showed negative GCA for PH and positive GCA for TSS, so they can be considered the best parents for crossings. Five hybrids showed both negative SCA for PH and positive GCA for TSS (LG x G53, Can x Laj, Can x Pi, Can x G53 and Pi x Laj).
Higher GCA effects indicate a greater role of additive effects controlling the traits, while higher SCA effects point to the importance of non-additive effects controlling the characteristics (Zhao et al. 2014). The presence of additive and non-additive effects controlling fruit traits indicates that the development of both homozygous lines and hybrids must be considered in P. angulata breeding programs. Additive and non-additive effects was also observed in traits of P. peruviana (Lagos et al. 2007) and P. ixocarpa (Montejo et al. 2015).
Using Additive and Mulamba-Rank indexes for PH and TSS, hybrids Can x G53, Can x LG, Pi x G53, Can x Pi and G53 x Pi were selected as the best P. angulata hybrids for both PH and TSS (Table 5). These hybrids had good performance and are from at least one of the parents with higher GCA, agreeing with the proposed by Cruz et al. (2012). It is expected that crossings using genitors with higher GCA lead to populations with higher means and crossings with higher SCA lead to populations with more variability (Mendonça et al. 2002). Considering this, hybrid Can x G53 have the higher potential to develop P. angulata populations with high mean and variability.
The occurrence of heterosis and heterobeltiosis in our study suggests that the use of hybrids in P. angulata must be considered aiming to increase yield and quality fruit traits. Additionally, the best hybrids can be used to produce segregating populations which can be applied to proceed genetic breeding or to make genetic studies. This is the rst report of diallel analysis and occurrence of additive and non-additive effects in P. angulata traits. Further studies are needed to nd the best conditions for evaluating P. angulata germplasm, especially for fruit traits.    (NSF) number of seeds per fruit; (FC) fruit color.