M S Dhaliwal

Growth and Yield of Tomato Influenced by Condition of Culture, Mulch, and Planting Date

ABSTRACT Below optimal temperatures can restrict growth of autumn planted tomato (Solanum lycopersicum L.), resulting in delayed fruiting and decreased fruit yield under field conditions. Technology for growing tomato under protected structures needs to be standardized. This study was conducted to determine effects of culture condition, planting date, and application of mulch on plant growth and fruit yield of tomato. To determine whether time of establishment affected results, plants were established in the first and third weeks of October and the first week of November of 2010 and 2011 in a polyhouse or open field using the mulch treatments black polyethylene, clear polyethylene, paddy straw, or no mulch. Root zone and air temperatures and net radiation were measured. Treatments affected plant height, fruit number, fruit weight, early yield, marketable yield, and total yield. Except for early yield, results were consistent between years. Black polyethylene mulch increased fruit number under the polyhouse and in the open field. Fruit weight was improved by mulch treatments only in the open field. Highest early, marketable, and total yields were from planting in the polyhouse in the third week of October using black polyethylene mulch, and this is attributed to increased root zone temperature, air temperature, and net radiation. Use of polyhouse and black plastic mulch combined with appropriate planting time improves early and total yields of tomato in areas where the production is constrained by suboptimal temperature conditions.

Genetic Diversity Analysis and DNA Fingerprinting of Elite Chilli Pepper Lines Using SSR Markers

Hybrid cultivars of chilli pepper (Capsicum annuum L.) have become very popular due to their superior performance. Punjab Agricultural University, Ludhiana, India, developed a genetic male sterile (GMS) line ‘MS-12’ by introducing a nuclear male sterility gene ms509 (redesignated as ms10) from a French introduction. Subsequently, ‘MS-12’ has successfully been used to develop commercial F1 hybrids. However, ‘MS-12’ has outlived its utility and there is a need to diversify the maternal parent. The investigation was carried out to identify the most divergent genotype from ‘MS-12’ among the six elite lines of chilli pepper by employing 58 SSR markers. Thirty produced polymorphic bands, revealing a total of 83 alleles with an average of 2.67 alleles per locus. Polymorphic information content (PIC) varied from 0.21 to 0.84, with an average value of 0.51. Based on PIC values and number of alleles amplified, the primer CAMS-072 was the most informative, followed by CAMS-311 and Hpms CaSIG-19. Lines under evaluation had more than 70% similar fragments. Dice similarity coefficients between any two genotypes varied from 0.70 to 0.95, with the lowest between ‘PBC-535’ with ‘VR-16’ and the highest between ‘MS-12’ sterile with ‘MS-12’ fertile. ‘SL-412’ and ‘DCL-524’ had a similarity coefficient of 0.93. Among the six elite lines assayed, ‘PBC-535’ was the most diverse from ‘MS-12’, followed by ‘VR-16’ with, similarity coefficients of 0.71 and 0.75, respectively. Some fragments were unique and can be used as cultivar specific markers for rapid discrimination. The discriminating power of these markers will be helpful in testing purity of F1 hybrids and for registering elite germplasm.

Mapping of fruit length related QTLs in interspecific cross ( Capsicum annuum L. × Capsicum galapagoense Hunz.) of chilli

Fruit length in chilli is quantitatively inherited trait and selection based on phenotypic performance is tedious and time consuming. To detect QTLs determining fruit length in Capsicum spp., an interspecific F2 mapping population was developed from the cross of C. annuum L. cv. ‘FL 201’ with C. galapagoense Hunz. accession ‘TC 07245’. Fruit length in this cross showed a quantitative inheritance with the population depicting a symmetric distribution in histogram. To map quantitative trait loci (QTLs) for fruit length 400 SSR markers were surveyed on the parental genotypes but only 28 markers were observed to be polymorphic indicating less genetic diversity between the two Capsicum species. Polymorphic markers were then analyzed in F2 population consisting of 210 plants and 24 of these markers were mapped on to three linkage groups (LGs): LG 1, LG 2 and LG 3. Two fruit length determining QTLs designated as paufl2.1 and paufl2.2 were identified and both the QTLs were mapped on to LG 2. The two QTLs together explained 21.78 per cent of the phenotypic variation. Apart from the two QTLs, positive alleles were detected in the small fruited parent ‘TC 07245’ which might be of potential use in chilli breeding programs.

Development of cytoplasmic male sterile lines in chilli ( Capsicum annuum L.) and their evaluation across multiple environments

A breeding program was initiated in 2009 to develop temperature stable CMS lines in chilli. ‘CCA 4261’ was used as a CMS donor. From the 11 testcross progeny screened, maintainer plants were identified from ‘SL 461’, ‘SL 462’ and ‘SD 463’. After 6 backcrosses to the maintainer plants, 17 CMS lines in diverse genetic backgrounds were established. The CMS lines were evaluated for stability of sterility over four environments during 2014–15 and 2015–16. The environments E1 and E3 represented the low temperature regime, and E2 and E4 the high temperature regime. The mean square values due to the genotypes and the environments were significant at p = 0.01 for pollen sterility (%), pollen release score, fruit setting (%) and number of seed fruit−1. The G × E interaction effects were significant for pollen sterility (%), fruit setting and number of seed fruit−1 and non-significant for pollen release score. Ten lines namely ‘CMS4611A’, ‘CMS4614A’, ‘CMS4622A’, ‘CMS4624A’, ‘CMS4626A’, ‘CMS46213A’, ‘CMS463D2A’, ‘CMS463D13A’, ‘CMS463D14A’ and ‘CMS463L5A’ were completely male sterile across the environments. Under open pollination conditions, the fruit and the seed setting ability of these lines was normal. The CMS transferred into the diverse genetic backgrounds would broaden the CMS germplasm resources in chilli.

Growth and yield of bell pepper as influenced by growing environment, mulch, and planting date

ABSTRACT Bell pepper (Capsicum annuum L. var. grossum Sendt.) production is often constrained by prevailing sub-optimal temperature conditions. The treatments that enhance earliness and extend availability period may substantially increase value of the crop. This two-year study (2010–11 and 2011–12) was conducted to investigate the comparative effect of two growing environments (open field vs. polyhouse), three planting dates (15 October, 30 October, and 15 November), and four mulch treatments (black polythene, clear polythene, paddy straw, and no-mulch) on growth and yield of bell pepper. The highest fruit number, fruit weight, early yield, marketable yield, and total yield were obtained when the crop was planted in the polyhouse on 30 October under black polythene mulch. Thus, the use of polyhouse and black plastic mulch, when combined with appropriate planting date, improves early and total yields of bell pepper in areas where the production is constrained by sub-optimal temperature conditions.

Validation of molecular marker AVRDC-PP12 linked to male sterility gene ms10 of chilli

The newly identified SSR marker AVRDC-PP12 linked to the male sterility gene ms10 distinguished the heterozygous (Ms10ms10) fertile from the homozygous (Ms10Ms10) fertile plants in chilli segregating populations. To assess efficiency of AVRDC-PP12 in marker-assisted backcrossing for transfer of ms10 gene; the marker was screened in four backcross progenies. The marker co-segregated with ms10 gene in three progenies derived from the crosses ‘MS-12 × VR-16’, ‘MS-12 × S-217621’ and ‘MS-12 × Selection Dev’ with recombination frequency of 3.22, 4.16 and 3.27%, respectively. The marker failed to differentiate the parents in the cross ‘MS-12 × DCL-524’and hence was not used for further genotyping of the population.

Combining Ability and Heterosis for Quality and Processing Traits in Chili Pepper (Capsicum annuum L.) Involving Male Sterile Lines

Non-availability of genetic male sterility (GMS) in genetically diverse genotypes and the problem of rouging fertile plants in hybrid plot necessitated the development and testing of new F1 hybrids of chili pepper (Capsicum annuum L.) using cytoplasmic-genetic male sterility (CGMS) system and identifying good combiner inbred lines for transferring male sterility system in to them. Twelve inbred lines including a CGMS and a GMS line were crossed in a half-diallel fashion following Griffing’s method II and model 1 (fixed effect). All 78 genotypes were evaluated for eight quality traits for two consecutive years at Ludhiana, India. Pooled analysis revealed that variances for parent × year were non-significant for all traits except capsaicin in oleoresin and coloring matter in oleoresin, whereas variances attributable to hybrid × year and parent vs. hybrid × year were significant for all traits except dry matter content and oleoresin content. Both GCA × Y and SCA × Y interactions were significant for all traits except dry matter content. The GMS line was a good combiner for six traits and the CGMS line for only one trait. Better parent heterosis of high magnitude was detected for powder yield (275%) and oleoresin yield (309%). The hybrids having high powder yield coupled with high dry matter content and those having low pungency in oleoresin were identified. We recommend that male sterility system be transferred into a few good combiner lines for cost-effective hybrid seed production and for broadening the genetic base of male sterile lines.