Floral Biology and Fruit Setting Studies in Chile. Ashish Saxena and Jarnail S Hundal

NMSU, Las Cruces PAU, Ludhiana 33 o

Punjab Agricultural University, Ludhiana ( Punjab state

Punjab Agricultural University, Ludhiana ( Punjab state

Capsicum annuum L. in Punjab Important cash crop  fresh market  processing industry. Higher net returns  diversification from  paddy (Oryza sativa L.)  wheat (Triticum aestivum L.) Excellent performers (hybrids)  CH 1  CH 3

Existing problem Required quantity of hybrid seed was not available. Available seed quality was poor due to low germination per cent. Hybrid seed production is problematic.

Floral Biology Study of life of flowers which includes initiation and anthesis of flowers, dehiscence of stamens, receptivity of stigma and development of fertilized ovary. Thorough knowledge is a pre requisite for embarking upon a crop breeding and hybridization program. Floral-biology of chile changes across different locations.

Seasonal variation Environment plays a pivotal role in fruit and seed formation. Temperature and relative humidity (RH) are the major contributing factors. Effects of climatic factors on floral biology, seed yield and seed quality are not well known.

So…

Objectives Optimize F1 seed production through other restorer lines Determine impact of environment on seed production.

How ??? Determine:  Pollen viability of male parents.  Fruit set of restorer lines when crossed with GMS (Genetic Male Sterile) line.  Seed germination of F1 seeds »Monthly during peak flowering season (June to September).

Materials & Methods

Genotypes MS 12 I 16 LLS Pepsi 8-1 PS 4221 Punjab Guchhedar S 2529 S 2530 S 2545 (Genetic Male Sterile) (1:1 male : female) X FemaleRestorer Lines

Identification of female in GMS CharacterMale fertileMale sterile PollenPresentAbsent Anther ColorLight GreyPurple or Yellow Anther sizeNormal Reduced to less than half Anther dehiscence PresentAbsent Fruit setHeavy Low to medium depend upon allogamy

CharacterMale fertileMale sterile PollenPresentAbsent Anther ColorLight GreyPurple or Yellow Anther sizeNormal Reduced to less than half Anther dehiscence PresentAbsent Fruit setHeavy Low to medium depend upon allogamy Uprooted before hand pollination Identification of female in GMS

CharacterMale fertileMale sterile PollenPresentAbsent Anther ColorLight GreyPurple or Yellow Anther sizeNormal Reduced to less than half Anther dehiscence PresentAbsent Fruit setHeavy Low to medium depend upon allogamy Used for hand pollination as female Identification of female in GMS

Pollen load Collection of freshly opened flowers Dehisced pollen dissolved in 1 μ L of dH 2 O with vertexer Pollens counted on hemocytometer

Pollen viability Collection of freshly open flowers Dehisce anthers at room temperature Preparation of glass slides with pollen and fresh TTC* Slides placed in dark for half an hour Observed under compound microscope for red staining * (2,3,5 triphenyl tetrazolium chloride) Viable pollen

Fruit set Identification of female plants in GMS line Hand pollination of 50 buds at 4 different periods by all 8 restorer lines separately Counting of fruits set after 5 days of crossing Four different periods are: [-12, 0, +12 and +24 h after anthesis]

Seed germination Collection of crossed seeds from female plants 25 seeds in 3 replications of each cross were placed on moist germination paper Placed in incubator at 25±1 0 C for 14 days Counting of germinated seeds

Statistical Analysis Randomized complete block design was used to analyze the data obtained from experiment. The data were pooled over different months to obtain useful results. CPCS 1 computer program was used for statistical analysis.

Observations

Restorer lines

Time -

LSD 0.05 = 2.0 Restorer lines e bb c b a d c

LSD 0.05 = 3.9 ccdcd cdecde dede b b a f Restorer lines

e e a bcbc f cdcd b dede LSD 0.05 = 4.6 Restorer lines

Results I  Maximum fruit set was observed when crossing was done at the time of anthesis.  S 2529 had highest pollen load and pollen viability, but lower fruit set prevent this restorer line to consider.  Punjab Guchhedar was the best restorer line for fruit set with highest germination of F1 seeds, despite lower pollen viability.  Significant genotype and environment interaction was observed.

Results II  Environment seems to play negligible role in determining the pollen viability.  Fruit set and seed germination ability greatly influenced by the temperature and relative humidity.  Average monthly temperature of 30 o C and 82% RH gave highest fruit set.  Highest seed germination was observed at 29 o C and 70% RH.

Conclusion  Punjab Guchhedar was the only restorer line performed consistently across different temperature and RH regimes from June to September months.  June and July months were found to be better for seed production of CH 1 hybrid.  August and September months were found to be better for seed production of CH 3 hybrid.